# sql.py # Copyright (C) 2005, 2006, 2007 Michael Bayer mike_mp@zzzcomputing.com # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """Define the base components of SQL expression trees. All components are derived from a common base class [sqlalchemy.sql#ClauseElement]. Common behaviors are organized based on class hierarchies, in some cases via mixins. All object construction from this package occurs via functions which in some cases will construct composite ``ClauseElement`` structures together, and in other cases simply return a single ``ClauseElement`` constructed directly. The function interface affords a more "DSL-ish" feel to constructing SQL expressions and also allows future class reorganizations. Even though classes are not constructed directly from the outside, most classes which have additional public methods are considered to be public (i.e. have no leading underscore). Other classes which are "semi-public" are marked with a single leading underscore; these classes usually have few or no public methods and are less guaranteed to stay the same in future releases. """ from sqlalchemy import util, exceptions, logging from sqlalchemy import types as sqltypes import string, re, random, sets __all__ = ['AbstractDialect', 'Alias', 'ClauseElement', 'ClauseParameters', 'ClauseVisitor', 'ColumnCollection', 'ColumnElement', 'Compiled', 'CompoundSelect', 'Executor', 'FromClause', 'Join', 'Select', 'Selectable', 'TableClause', 'alias', 'and_', 'asc', 'between_', 'between', 'bindparam', 'case', 'cast', 'column', 'delete', 'desc', 'distinct', 'except_', 'except_all', 'exists', 'extract', 'func', 'modifier', 'insert', 'intersect', 'intersect_all', 'join', 'literal', 'literal_column', 'not_', 'null', 'or_', 'outerjoin', 'select', 'subquery', 'table', 'text', 'union', 'union_all', 'update',] # precedence ordering for common operators. if an operator is not present in this list, # it will be parenthesized when grouped against other operators PRECEDENCE = { 'FROM':15, '*':7, '/':7, '%':7, '+':6, '-':6, 'ILIKE':5, 'NOT ILIKE':5, 'LIKE':5, 'NOT LIKE':5, 'IN':5, 'NOT IN':5, 'IS':5, 'IS NOT':5, '=':5, '!=':5, '>':5, '<':5, '>=':5, '<=':5, 'BETWEEN':5, 'DISTINCT':5, 'NOT':5, 'AND':3, 'OR':2, ',':-1, 'AS':-1, 'EXISTS':0, '_smallest': -1000, '_largest': 1000 } def desc(column): """Return a descending ``ORDER BY`` clause element. E.g.:: order_by = [desc(table1.mycol)] """ return _UnaryExpression(column, modifier="DESC") def asc(column): """Return an ascending ``ORDER BY`` clause element. E.g.:: order_by = [asc(table1.mycol)] """ return _UnaryExpression(column, modifier="ASC") def outerjoin(left, right, onclause=None, **kwargs): """Return an ``OUTER JOIN`` clause element. The returned object is an instance of [sqlalchemy.sql#Join]. Similar functionality is also available via the ``outerjoin()`` method on any [sqlalchemy.sql#FromClause]. left The left side of the join. right The right side of the join. onclause Optional criterion for the ``ON`` clause, is derived from foreign key relationships established between left and right otherwise. To chain joins together, use the ``join()`` or ``outerjoin()`` methods on the resulting ``Join`` object. """ return Join(left, right, onclause, isouter = True, **kwargs) def join(left, right, onclause=None, **kwargs): """Return a ``JOIN`` clause element (regular inner join). The returned object is an instance of [sqlalchemy.sql#Join]. Similar functionality is also available via the ``join()`` method on any [sqlalchemy.sql#FromClause]. left The left side of the join. right The right side of the join. onclause Optional criterion for the ``ON`` clause, is derived from foreign key relationships established between left and right otherwise. To chain joins together, use the ``join()`` or ``outerjoin()`` methods on the resulting ``Join`` object. """ return Join(left, right, onclause, **kwargs) def select(columns=None, whereclause = None, from_obj = [], **kwargs): """Returns a ``SELECT`` clause element. Similar functionality is also available via the ``select()`` method on any [sqlalchemy.sql#FromClause]. The returned object is an instance of [sqlalchemy.sql#Select]. All arguments which accept ``ClauseElement`` arguments also accept string arguments, which will be converted as appropriate into either ``text()`` or ``literal_column()`` constructs. columns A list of ``ClauseElement`` objects, typically ``ColumnElement`` objects or subclasses, which will form the columns clause of the resulting statement. For all members which are instances of ``Selectable``, the individual ``ColumnElement`` members of the ``Selectable`` will be added individually to the columns clause. For example, specifying a ``Table`` instance will result in all the contained ``Column`` objects within to be added to the columns clause. This argument is not present on the form of ``select()`` available on ``Table``. whereclause A ``ClauseElement`` expression which will be used to form the ``WHERE`` clause. from_obj A list of ``ClauseElement`` objects which will be added to the ``FROM`` clause of the resulting statement. Note that "from" objects are automatically located within the columns and whereclause ClauseElements. Use this parameter to explicitly specify "from" objects which are not automatically locatable. This could include ``Table`` objects that aren't otherwise present, or ``Join`` objects whose presence will supercede that of the ``Table`` objects already located in the other clauses. \**kwargs Additional parameters include: order_by a scalar or list of ``ClauseElement`` objects which will comprise the ``ORDER BY`` clause of the resulting select. group_by a list of ``ClauseElement`` objects which will comprise the ``GROUP BY`` clause of the resulting select. having a ``ClauseElement`` that will comprise the ``HAVING`` clause of the resulting select when ``GROUP BY`` is used. use_labels=False when ``True``, the statement will be generated using labels for each column in the columns clause, which qualify each column with its parent table's (or aliases) name so that name conflicts between columns in different tables don't occur. The format of the label is _. The "c" collection of the resulting ``Select`` object will use these names as well for targeting column members. distinct=False when ``True``, applies a ``DISTINCT`` qualifier to the columns clause of the resulting statement. for_update=False when ``True``, applies ``FOR UPDATE`` to the end of the resulting statement. Certain database dialects also support alternate values for this parameter, for example mysql supports "read" which translates to ``LOCK IN SHARE MODE``, and oracle supports "nowait" which translates to ``FOR UPDATE NOWAIT``. bind=None an ``Engine`` or ``Connection`` instance to which the resulting ``Select`` object will be bound. The ``Select`` object will otherwise automatically bind to whatever ``Connectable`` instances can be located within its contained ``ClauseElement`` members. engine=None deprecated. a synonym for "bind". limit=None a numerical value which usually compiles to a ``LIMIT`` expression in the resulting select. Databases that don't support ``LIMIT`` will attempt to provide similar functionality. offset=None a numerical value which usually compiles to an ``OFFSET`` expression in the resulting select. Databases that don't support ``OFFSET`` will attempt to provide similar functionality. scalar=False when ``True``, indicates that the resulting ``Select`` object is to be used in the "columns" clause of another select statement, where the evaluated value of the column is the scalar result of this statement. Normally, placing any ``Selectable`` within the columns clause of a ``select()`` call will expand the member columns of the ``Selectable`` individually. correlate=True indicates that this ``Select`` object should have its contained ``FromClause`` elements "correlated" to an enclosing ``Select`` object. This means that any ``ClauseElement`` instance within the "froms" collection of this ``Select`` which is also present in the "froms" collection of an enclosing select will not be rendered in the ``FROM`` clause of this select statement. """ return Select(columns, whereclause = whereclause, from_obj = from_obj, **kwargs) def subquery(alias, *args, **kwargs): """Return an [sqlalchemy.sql#Alias] object derived from a [sqlalchemy.sql#Select]. name alias name \*args, \**kwargs all other arguments are delivered to the [sqlalchemy.sql#select()] function. """ return Select(*args, **kwargs).alias(alias) def insert(table, values = None, **kwargs): """Return an [sqlalchemy.sql#_Insert] clause element. Similar functionality is available via the ``insert()`` method on [sqlalchemy.schema#Table]. table The table to be inserted into. values A dictionary which specifies the column specifications of the ``INSERT``, and is optional. If left as None, the column specifications are determined from the bind parameters used during the compile phase of the ``INSERT`` statement. If the bind parameters also are None during the compile phase, then the column specifications will be generated from the full list of table columns. If both `values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within `values` on a per-key basis. The keys within `values` can be either ``Column`` objects or their string identifiers. Each key may reference one of: * a literal data value (i.e. string, number, etc.); * a Column object; * a SELECT statement. If a ``SELECT`` statement is specified which references this ``INSERT`` statement's table, the statement will be correlated against the ``INSERT`` statement. """ return _Insert(table, values, **kwargs) def update(table, whereclause = None, values = None, **kwargs): """Return an [sqlalchemy.sql#_Update] clause element. Similar functionality is available via the ``update()`` method on [sqlalchemy.schema#Table]. table The table to be updated. whereclause A ``ClauseElement`` describing the ``WHERE`` condition of the ``UPDATE`` statement. values A dictionary which specifies the ``SET`` conditions of the ``UPDATE``, and is optional. If left as None, the ``SET`` conditions are determined from the bind parameters used during the compile phase of the ``UPDATE`` statement. If the bind parameters also are None during the compile phase, then the ``SET`` conditions will be generated from the full list of table columns. If both `values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within `values` on a per-key basis. The keys within `values` can be either ``Column`` objects or their string identifiers. Each key may reference one of: * a literal data value (i.e. string, number, etc.); * a Column object; * a SELECT statement. If a ``SELECT`` statement is specified which references this ``UPDATE`` statement's table, the statement will be correlated against the ``UPDATE`` statement. """ return _Update(table, whereclause, values, **kwargs) def delete(table, whereclause = None, **kwargs): """Return a [sqlalchemy.sql#_Delete] clause element. Similar functionality is available via the ``delete()`` method on [sqlalchemy.schema#Table]. table The table to be updated. whereclause A ``ClauseElement`` describing the ``WHERE`` condition of the ``UPDATE`` statement. """ return _Delete(table, whereclause, **kwargs) def and_(*clauses): """Join a list of clauses together using the ``AND`` operator. The ``&`` operator is also overloaded on all [sqlalchemy.sql#_CompareMixin] subclasses to produce the same result. """ if len(clauses) == 1: return clauses[0] return ClauseList(operator='AND', *clauses) def or_(*clauses): """Join a list of clauses together using the ``OR`` operator. The ``|`` operator is also overloaded on all [sqlalchemy.sql#_CompareMixin] subclasses to produce the same result. """ if len(clauses) == 1: return clauses[0] return ClauseList(operator='OR', *clauses) def not_(clause): """Return a negation of the given clause, i.e. ``NOT(clause)``. The ``~`` operator is also overloaded on all [sqlalchemy.sql#_CompareMixin] subclasses to produce the same result. """ return clause._negate() def distinct(expr): """return a ``DISTINCT`` clause.""" return _UnaryExpression(expr, operator="DISTINCT") def between(ctest, cleft, cright): """Return a ``BETWEEN`` predicate clause. Equivalent of SQL ``clausetest BETWEEN clauseleft AND clauseright``. The ``between()`` method on all [sqlalchemy.sql#_CompareMixin] subclasses provides similar functionality. """ return _BinaryExpression(ctest, ClauseList(_literals_as_binds(cleft, type=ctest.type), _literals_as_binds(cright, type=ctest.type), operator='AND', group=False), 'BETWEEN') def between_(*args, **kwargs): """synonym for [sqlalchemy.sql#between()] (deprecated).""" return between(*args, **kwargs) def case(whens, value=None, else_=None): """Produce a ``CASE`` statement. whens A sequence of pairs to be translated into "when / then" clauses. value Optional for simple case statements. else\_ Optional as well, for case defaults. """ whenlist = [ClauseList('WHEN', c, 'THEN', r, operator=None) for (c,r) in whens] if not else_ is None: whenlist.append(ClauseList('ELSE', else_, operator=None)) if len(whenlist): type = list(whenlist[-1])[-1].type else: type = None cc = _CalculatedClause(None, 'CASE', value, type=type, operator=None, group_contents=False, *whenlist + ['END']) return cc def cast(clause, totype, **kwargs): """Return a ``CAST`` function. Equivalent of SQL ``CAST(clause AS totype)``. Use with a [sqlalchemy.types#TypeEngine] subclass, i.e:: cast(table.c.unit_price * table.c.qty, Numeric(10,4)) or:: cast(table.c.timestamp, DATE) """ return _Cast(clause, totype, **kwargs) def extract(field, expr): """Return the clause ``extract(field FROM expr)``.""" expr = _BinaryExpression(text(field), expr, "FROM") return func.extract(expr) def exists(*args, **kwargs): """Return an ``EXISTS`` clause as applied to a [sqlalchemy.sql#Select] object. The resulting [sqlalchemy.sql#_Exists] object can be executed by itself or used as a subquery within an enclosing select. \*args, \**kwargs all arguments are sent directly to the [sqlalchemy.sql#select()] function to produce a ``SELECT`` statement. """ return _Exists(*args, **kwargs) def union(*selects, **kwargs): """Return a ``UNION`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. A similar ``union()`` method is available on all [sqlalchemy.sql#FromClause] subclasses. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('UNION', *selects, **kwargs) def union_all(*selects, **kwargs): """Return a ``UNION ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. A similar ``union_all()`` method is available on all [sqlalchemy.sql#FromClause] subclasses. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('UNION ALL', *selects, **kwargs) def except_(*selects, **kwargs): """Return an ``EXCEPT`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('EXCEPT', *selects, **kwargs) def except_all(*selects, **kwargs): """Return an ``EXCEPT ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('EXCEPT ALL', *selects, **kwargs) def intersect(*selects, **kwargs): """Return an ``INTERSECT`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('INTERSECT', *selects, **kwargs) def intersect_all(*selects, **kwargs): """Return an ``INTERSECT ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql#CompoundSelect]. \*selects a list of [sqlalchemy.sql#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql#select()]. """ return _compound_select('INTERSECT ALL', *selects, **kwargs) def alias(selectable, alias=None): """Return an [sqlalchemy.sql#Alias] object. An ``Alias`` represents any [sqlalchemy.sql#FromClause] with an alternate name assigned within SQL, typically using the ``AS`` clause when generated, e.g. ``SELECT * FROM table AS aliasname``. Similar functionality is available via the ``alias()`` method available on all ``FromClause`` subclasses. selectable any ``FromClause`` subclass, such as a table, select statement, etc.. alias string name to be assigned as the alias. If ``None``, a random name will be generated. """ return Alias(selectable, alias=alias) def literal(value, type=None): """Return a literal clause, bound to a bind parameter. Literal clauses are created automatically when non- ``ClauseElement`` objects (such as strings, ints, dates, etc.) are used in a comparison operation with a [sqlalchemy.sql#_CompareMixin] subclass, such as a ``Column`` object. Use this function to force the generation of a literal clause, which will be created as a [sqlalchemy.sql#_BindParamClause] with a bound value. value the value to be bound. can be any Python object supported by the underlying DBAPI, or is translatable via the given type argument. type an optional [sqlalchemy.types#TypeEngine] which will provide bind-parameter translation for this literal. """ return _BindParamClause('literal', value, type=type, unique=True) def label(name, obj): """Return a [sqlalchemy.sql#_Label] object for the given [sqlalchemy.sql#ColumnElement]. A label changes the name of an element in the columns clause of a ``SELECT`` statement, typically via the ``AS`` SQL keyword. This functionality is more conveniently available via the ``label()`` method on ``ColumnElement``. name label name obj a ``ColumnElement``. """ return _Label(name, obj) def column(text, type=None): """Return a textual column clause, as would be in the columns clause of a ``SELECT`` statement. The object returned is an instance of [sqlalchemy.sql#_ColumnClause], which represents the "syntactical" portion of the schema-level [sqlalchemy.schema#Column] object. text the name of the column. Quoting rules will be applied to the clause like any other column name. For textual column constructs that are not to be quoted, use the [sqlalchemy.sql#literal_column()] function. type an optional [sqlalchemy.types#TypeEngine] object which will provide result-set translation for this column. """ return _ColumnClause(text, type=type) def literal_column(text, type=None): """Return a textual column clause, as would be in the columns clause of a ``SELECT`` statement. The object returned is an instance of [sqlalchemy.sql#_ColumnClause], which represents the "syntactical" portion of the schema-level [sqlalchemy.schema#Column] object. text the name of the column. Quoting rules will not be applied to the column. For textual column constructs that should be quoted like any other column construct, use the [sqlalchemy.sql#column()] function. type an optional [sqlalchemy.types#TypeEngine] object which will provide result-set translation for this column. """ return _ColumnClause(text, type=type, is_literal=True) def table(name, *columns): """Return a [sqlalchemy.sql#Table] object. This is a primitive version of the [sqlalchemy.schema#Table] object, which is a subclass of this object. """ return TableClause(name, *columns) def bindparam(key, value=None, type=None, shortname=None, unique=False): """Create a bind parameter clause with the given key. value a default value for this bind parameter. a bindparam with a value is called a ``value-based bindparam``. shortname an ``alias`` for this bind parameter. usually used to alias the ``key`` and ``label`` of a column, i.e. ``somecolname`` and ``sometable_somecolname`` type a sqlalchemy.types.TypeEngine object indicating the type of this bind param, will invoke type-specific bind parameter processing unique if True, bind params sharing the same name will have their underlying ``key`` modified to a uniquely generated name. mostly useful with value-based bind params. """ if isinstance(key, _ColumnClause): return _BindParamClause(key.name, value, type=key.type, shortname=shortname, unique=unique) else: return _BindParamClause(key, value, type=type, shortname=shortname, unique=unique) def text(text, bind=None, engine=None, *args, **kwargs): """Create literal text to be inserted into a query. When constructing a query from a ``select()``, ``update()``, ``insert()`` or ``delete()``, using plain strings for argument values will usually result in text objects being created automatically. Use this function when creating textual clauses outside of other ``ClauseElement`` objects, or optionally wherever plain text is to be used. text The text of the SQL statement to be created. use ``:`` to specify bind parameters; they will be compiled to their engine-specific format. bind An optional connection or engine to be used for this text query. engine deprecated. a synonym for 'bind'. bindparams A list of ``bindparam()`` instances which can be used to define the types and/or initial values for the bind parameters within the textual statement; the keynames of the bindparams must match those within the text of the statement. The types will be used for pre-processing on bind values. typemap A dictionary mapping the names of columns represented in the ``SELECT`` clause of the textual statement to type objects, which will be used to perform post-processing on columns within the result set (for textual statements that produce result sets). """ return _TextClause(text, engine=engine, bind=bind, *args, **kwargs) def null(): """Return a ``_Null`` object, which compiles to ``NULL`` in a sql statement.""" return _Null() class _FunctionGenerator(object): """Generate ``_Function`` objects based on getattr calls.""" def __init__(self, **opts): self.__names = [] self.opts = opts def __getattr__(self, name): if name[-1] == '_': name = name[0:-1] f = _FunctionGenerator(**self.opts) f.__names = list(self.__names) + [name] return f def __call__(self, *c, **kwargs): o = self.opts.copy() o.update(kwargs) return _Function(self.__names[-1], packagenames=self.__names[0:-1], *c, **o) func = _FunctionGenerator() # TODO: use UnaryExpression for this instead ? modifier = _FunctionGenerator(group=False) def _compound_select(keyword, *selects, **kwargs): return CompoundSelect(keyword, *selects, **kwargs) def _is_literal(element): return not isinstance(element, ClauseElement) def _literals_as_text(element): if _is_literal(element): return _TextClause(unicode(element)) else: return element def _literals_as_binds(element, name='literal', type=None): if _is_literal(element): if element is None: return null() else: return _BindParamClause(name, element, shortname=name, type=type, unique=True) else: return element def is_column(col): return isinstance(col, ColumnElement) class AbstractDialect(object): """Represent the behavior of a particular database. Used by ``Compiled`` objects.""" pass class ClauseParameters(object): """Represent a dictionary/iterator of bind parameter key names/values. Tracks the original [sqlalchemy.sql#_BindParamClause] objects as well as the keys/position of each parameter, and can return parameters as a dictionary or a list. Will process parameter values according to the ``TypeEngine`` objects present in the ``_BindParamClause`` instances. """ def __init__(self, dialect, positional=None): super(ClauseParameters, self).__init__() self.dialect = dialect self.binds = {} self.binds_to_names = {} self.binds_to_values = {} self.positional = positional or [] def set_parameter(self, bindparam, value, name): self.binds[bindparam.key] = bindparam self.binds[name] = bindparam self.binds_to_names[bindparam] = name self.binds_to_values[bindparam] = value def get_original(self, key): """Return the given parameter as it was originally placed in this ``ClauseParameters`` object, without any ``Type`` conversion.""" return self.binds_to_values[self.binds[key]] def get_processed(self, key): bind = self.binds[key] value = self.binds_to_values[bind] return bind.typeprocess(value, self.dialect) def keys(self): return self.binds_to_names.values() def __getitem__(self, key): return self.get_processed(key) def __contains__(self, key): return key in self.binds def set_value(self, key, value): bind = self.binds[key] self.binds_to_values[bind] = value def get_original_dict(self): return dict([(self.binds_to_names[b], self.binds_to_values[b]) for b in self.binds_to_names.keys()]) def get_raw_list(self): return [self.get_processed(key) for key in self.positional] def get_raw_dict(self): d = {} for k in self.binds_to_names.values(): d[k] = self.get_processed(k) return d def __repr__(self): return self.__class__.__name__ + ":" + repr(self.get_original_dict()) class ClauseVisitor(object): """A class that knows how to traverse and visit ``ClauseElements``. Each ``ClauseElement``'s accept_visitor() method will call a corresponding visit_XXXX() method here. Traversal of a hierarchy of ``ClauseElements`` is achieved via the ``traverse()`` method, which is passed the lead ``ClauseElement``. By default, ``ClauseVisitor`` traverses all elements fully. Options can be specified at the class level via the ``__traverse_options__`` dictionary which will be passed to the ``get_children()`` method of each ``ClauseElement``; these options can indicate modifications to the set of elements returned, such as to not return column collections (column_collections=False) or to return Schema-level items (schema_visitor=True).""" __traverse_options__ = {} def traverse(self, obj, stop_on=None): stack = [obj] traversal = [] while len(stack) > 0: t = stack.pop() if stop_on is None or t not in stop_on: traversal.insert(0, t) for c in t.get_children(**self.__traverse_options__): stack.append(c) for target in traversal: v = self while v is not None: target.accept_visitor(v) v = getattr(v, '_next', None) return obj def chain(self, visitor): """'chain' an additional ClauseVisitor onto this ClauseVisitor. the chained visitor will receive all visit events after this one.""" tail = self while getattr(tail, '_next', None) is not None: tail = tail._next tail._next = visitor return self def visit_column(self, column): pass def visit_table(self, table): pass def visit_fromclause(self, fromclause): pass def visit_bindparam(self, bindparam): pass def visit_textclause(self, textclause): pass def visit_compound(self, compound): pass def visit_compound_select(self, compound): pass def visit_binary(self, binary): pass def visit_unary(self, unary): pass def visit_alias(self, alias): pass def visit_select(self, select): pass def visit_join(self, join): pass def visit_null(self, null): pass def visit_clauselist(self, list): pass def visit_calculatedclause(self, calcclause): pass def visit_grouping(self, gr): pass def visit_function(self, func): pass def visit_cast(self, cast): pass def visit_label(self, label): pass def visit_typeclause(self, typeclause): pass class LoggingClauseVisitor(ClauseVisitor): """extends ClauseVisitor to include debug logging of all traversal. To install this visitor, set logging.DEBUG for 'sqlalchemy.sql.ClauseVisitor' **before** you import the sqlalchemy.sql module. """ def traverse(self, obj, stop_on=None): stack = [(obj, "")] traversal = [] while len(stack) > 0: (t, indent) = stack.pop() if stop_on is None or t not in stop_on: traversal.insert(0, (t, indent)) for c in t.get_children(**self.__traverse_options__): stack.append((c, indent + " ")) for (target, indent) in traversal: self.logger.debug(indent + repr(target)) v = self while v is not None: target.accept_visitor(v) v = getattr(v, '_next', None) return obj LoggingClauseVisitor.logger = logging.class_logger(ClauseVisitor) if logging.is_debug_enabled(LoggingClauseVisitor.logger): ClauseVisitor=LoggingClauseVisitor class NoColumnVisitor(ClauseVisitor): """a ClauseVisitor that will not traverse the exported Column collections on Table, Alias, Select, and CompoundSelect objects (i.e. their 'columns' or 'c' attribute). this is useful because most traversals don't need those columns, or in the case of ANSICompiler it traverses them explicitly; so skipping their traversal here greatly cuts down on method call overhead. """ __traverse_options__ = {'column_collections':False} class Executor(object): """Interface representing a "thing that can produce Compiled objects and execute them".""" def execute_compiled(self, compiled, parameters, echo=None, **kwargs): """Execute a Compiled object.""" raise NotImplementedError() def compiler(self, statement, parameters, **kwargs): """Return a Compiled object for the given statement and parameters.""" raise NotImplementedError() class Compiled(ClauseVisitor): """Represent a compiled SQL expression. The ``__str__`` method of the ``Compiled`` object should produce the actual text of the statement. ``Compiled`` objects are specific to their underlying database dialect, and also may or may not be specific to the columns referenced within a particular set of bind parameters. In no case should the ``Compiled`` object be dependent on the actual values of those bind parameters, even though it may reference those values as defaults. """ def __init__(self, dialect, statement, parameters, bind=None, engine=None): """Construct a new ``Compiled`` object. statement ``ClauseElement`` to be compiled. parameters Optional dictionary indicating a set of bind parameters specified with this ``Compiled`` object. These parameters are the *default* values corresponding to the ``ClauseElement``'s ``_BindParamClauses`` when the ``Compiled`` is executed. In the case of an ``INSERT`` or ``UPDATE`` statement, these parameters will also result in the creation of new ``_BindParamClause`` objects for each key and will also affect the generated column list in an ``INSERT`` statement and the ``SET`` clauses of an ``UPDATE`` statement. The keys of the parameter dictionary can either be the string names of columns or ``_ColumnClause`` objects. bind optional engine or connection which will be bound to the compiled object. engine deprecated, a synonym for 'bind' """ self.dialect = dialect self.statement = statement self.parameters = parameters self.bind = bind or engine self.can_execute = statement.supports_execution() def compile(self): self.traverse(self.statement) self.after_compile() def __str__(self): """Return the string text of the generated SQL statement.""" raise NotImplementedError() def get_params(self, **params): """Deprecated. use construct_params(). (supports unicode names) """ return self.construct_params(params) def construct_params(self, params): """Return the bind params for this compiled object. Will start with the default parameters specified when this ``Compiled`` object was first constructed, and will override those values with those sent via `**params`, which are key/value pairs. Each key should match one of the ``_BindParamClause`` objects compiled into this object; either the `key` or `shortname` property of the ``_BindParamClause``. """ raise NotImplementedError() def execute(self, *multiparams, **params): """Execute this compiled object.""" e = self.bind if e is None: raise exceptions.InvalidRequestError("This Compiled object is not bound to any Engine or Connection.") return e.execute_compiled(self, *multiparams, **params) def scalar(self, *multiparams, **params): """Execute this compiled object and return the result's scalar value.""" return self.execute(*multiparams, **params).scalar() class ClauseElement(object): """Base class for elements of a programmatically constructed SQL expression. """ def _get_from_objects(self): """Return objects represented in this ``ClauseElement`` that should be added to the ``FROM`` list of a query, when this ``ClauseElement`` is placed in the column clause of a ``Select`` statement. """ raise NotImplementedError(repr(self)) def _hide_froms(self): """Return a list of ``FROM`` clause elements which this ``ClauseElement`` replaces. """ return [] def compare(self, other): """Compare this ClauseElement to the given ClauseElement. Subclasses should override the default behavior, which is a straight identity comparison. """ return self is other def accept_visitor(self, visitor): """Accept a ``ClauseVisitor`` and call the appropriate ``visit_xxx`` method. """ raise NotImplementedError(repr(self)) def get_children(self, **kwargs): """return immediate child elements of this ``ClauseElement``. this is used for visit traversal. \**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).""" return [] def self_group(self, against=None): return self def supports_execution(self): """Return True if this clause element represents a complete executable statement. """ return False def copy_container(self): """Return a copy of this ``ClauseElement``, if this ``ClauseElement`` contains other ``ClauseElements``. If this ``ClauseElement`` is not a container, it should return self. This is used to create copies of expression trees that still reference the same *leaf nodes*. The new structure can then be restructured without affecting the original. """ return self def _find_engine(self): """Default strategy for locating an engine within the clause element. Relies upon a local engine property, or looks in the *from* objects which ultimately have to contain Tables or TableClauses. """ try: if self._bind is not None: return self._bind except AttributeError: pass for f in self._get_from_objects(): if f is self: continue engine = f.bind if engine is not None: return engine else: return None bind = property(lambda s:s._find_engine(), doc="""Returns the Engine or Connection to which this ClauseElement is bound, or None if none found.""") engine = bind def execute(self, *multiparams, **params): """Compile and execute this ``ClauseElement``.""" if len(multiparams): compile_params = multiparams[0] else: compile_params = params return self.compile(bind=self.bind, parameters=compile_params).execute(*multiparams, **params) def scalar(self, *multiparams, **params): """Compile and execute this ``ClauseElement``, returning the result's scalar representation. """ return self.execute(*multiparams, **params).scalar() def compile(self, bind=None, engine=None, parameters=None, compiler=None, dialect=None): """Compile this SQL expression. Uses the given ``Compiler``, or the given ``AbstractDialect`` or ``Engine`` to create a ``Compiler``. If no `compiler` arguments are given, tries to use the underlying ``Engine`` this ``ClauseElement`` is bound to to create a ``Compiler``, if any. Finally, if there is no bound ``Engine``, uses an ``ANSIDialect`` to create a default ``Compiler``. `parameters` is a dictionary representing the default bind parameters to be used with the statement. If `parameters` is a list, it is assumed to be a list of dictionaries and the first dictionary in the list is used with which to compile against. The bind parameters can in some cases determine the output of the compilation, such as for ``UPDATE`` and ``INSERT`` statements the bind parameters that are present determine the ``SET`` and ``VALUES`` clause of those statements. """ if (isinstance(parameters, list) or isinstance(parameters, tuple)): parameters = parameters[0] if compiler is None: if dialect is not None: compiler = dialect.compiler(self, parameters) elif bind is not None: compiler = bind.compiler(self, parameters) elif engine is not None: compiler = engine.compiler(self, parameters) elif self.bind is not None: compiler = self.bind.compiler(self, parameters) if compiler is None: import sqlalchemy.ansisql as ansisql compiler = ansisql.ANSIDialect().compiler(self, parameters=parameters) compiler.compile() return compiler def __str__(self): return unicode(self.compile()).encode('ascii', 'backslashreplace') def __and__(self, other): return and_(self, other) def __or__(self, other): return or_(self, other) def __invert__(self): return self._negate() def _negate(self): return _UnaryExpression(self.self_group(against="NOT"), operator="NOT", negate=None) class _CompareMixin(object): """Defines comparison operations for ``ClauseElement`` instances. This is a mixin class that adds the capability to produce ``ClauseElement`` instances based on regular Python operators. These operations are achieved using Python's operator overload methods (i.e. ``__eq__()``, ``__ne__()``, etc. Overridden operators include all comparison operators (i.e. '==', '!=', '<'), math operators ('+', '-', '*', etc), the '&' and '|' operators which evaluate to ``AND`` and ``OR`` respectively. Other methods exist to create additional SQL clauses such as ``IN``, ``LIKE``, ``DISTINCT``, etc. """ def __lt__(self, other): return self._compare('<', other) def __le__(self, other): return self._compare('<=', other) def __eq__(self, other): return self._compare('=', other) def __ne__(self, other): return self._compare('!=', other) def __gt__(self, other): return self._compare('>', other) def __ge__(self, other): return self._compare('>=', other) def like(self, other): """produce a ``LIKE`` clause.""" return self._compare('LIKE', other) def in_(self, *other): """produce an ``IN`` clause.""" if len(other) == 0: return _Grouping(case([(self.__eq__(None), text('NULL'))], else_=text('0')).__eq__(text('1'))) elif len(other) == 1: o = other[0] if _is_literal(o) or isinstance( o, _CompareMixin): return self.__eq__( o) #single item -> == else: assert hasattr( o, '_selectable') #better check? return self._compare( 'IN', o, negate='NOT IN') #single selectable args = [] for o in other: if not _is_literal(o): if not isinstance( o, _CompareMixin): raise exceptions.InvalidRequestError( "in() function accepts either non-selectable values, or a single selectable: "+repr(o) ) else: o = self._bind_param(o) args.append(o) return self._compare( 'IN', ClauseList(*args).self_group(against='IN'), negate='NOT IN') def startswith(self, other): """produce the clause ``LIKE '%'``""" perc = isinstance(other,(str,unicode)) and '%' or literal('%',type= sqltypes.String) return self._compare('LIKE', other + perc) def endswith(self, other): """produce the clause ``LIKE '%'``""" if isinstance(other,(str,unicode)): po = '%' + other else: po = literal('%', type= sqltypes.String) + other po.type = sqltypes.to_instance( sqltypes.String) #force! return self._compare('LIKE', po) def __radd__(self, other): return self._bind_param(other)._operate('+', self) def __rsub__(self, other): return self._bind_param(other)._operate('-', self) def __rmul__(self, other): return self._bind_param(other)._operate('*', self) def __rdiv__(self, other): return self._bind_param(other)._operate('/', self) def label(self, name): """produce a column label, i.e. `` AS ``""" return _Label(name, self, self.type) def distinct(self): """produce a DISTINCT clause, i.e. ``DISTINCT ``""" return _UnaryExpression(self, operator="DISTINCT") def between(self, cleft, cright): """produce a BETWEEN clause, i.e. `` BETWEEN AND ``""" return _BinaryExpression(self, ClauseList(self._check_literal(cleft), self._check_literal(cright), operator='AND', group=False), 'BETWEEN') def op(self, operator): """produce a generic operator function. e.g. somecolumn.op("*")(5) produces somecolumn * 5 operator a string which will be output as the infix operator between this ``ClauseElement`` and the expression passed to the generated function. """ return lambda other: self._operate(operator, other) # and here come the math operators: def __add__(self, other): return self._operate('+', other) def __sub__(self, other): return self._operate('-', other) def __mul__(self, other): return self._operate('*', other) def __div__(self, other): return self._operate('/', other) def __mod__(self, other): return self._operate('%', other) def __truediv__(self, other): return self._operate('/', other) def _bind_param(self, obj): return _BindParamClause('literal', obj, shortname=None, type=self.type, unique=True) def _check_literal(self, other): if _is_literal(other): return self._bind_param(other) else: return other def _compare(self, operator, obj, negate=None): if obj is None or isinstance(obj, _Null): if operator == '=': return _BinaryExpression(self._compare_self(), null(), 'IS', negate='IS NOT') elif operator == '!=': return _BinaryExpression(self._compare_self(), null(), 'IS NOT', negate='IS') else: raise exceptions.ArgumentError("Only '='/'!=' operators can be used with NULL") else: obj = self._check_literal(obj) return _BinaryExpression(self._compare_self(), obj, operator, type=self._compare_type(obj), negate=negate) def _operate(self, operator, obj): if _is_literal(obj): obj = self._bind_param(obj) return _BinaryExpression(self._compare_self(), obj, operator, type=self._compare_type(obj)) def _compare_self(self): """Allow ``ColumnImpl`` to return its ``Column`` object for usage in ``ClauseElements``, all others to just return self. """ return self def _compare_type(self, obj): """Allow subclasses to override the type used in constructing ``_BinaryExpression`` objects. Default return value is the type of the given object. """ return obj.type class Selectable(ClauseElement): """Represent a column list-holding object. this is the common base class of [sqlalchemy.sql#ColumnElement] and [sqlalchemy.sql#FromClause]. The reason ``ColumnElement`` is marked as a "list-holding" object is so that it can be treated similarly to ``FromClause`` in column-selection scenarios; it contains a list of columns consisting of itself. """ columns = util.NotImplProperty("""a [sqlalchemy.sql#ColumnCollection] containing ``ColumnElement`` instances.""") def _selectable(self): return self def accept_visitor(self, visitor): raise NotImplementedError(repr(self)) def select(self, whereclauses = None, **params): return select([self], whereclauses, **params) def _group_parenthesized(self): """Indicate if this ``Selectable`` requires parenthesis when grouped into a compound statement. """ return True class ColumnElement(Selectable, _CompareMixin): """Represent an element that is useable within the "column clause" portion of a ``SELECT`` statement. This includes columns associated with tables, aliases, and subqueries, expressions, function calls, SQL keywords such as ``NULL``, literals, etc. ``ColumnElement`` is the ultimate base class for all such elements. ``ColumnElement`` supports the ability to be a *proxy* element, which indicates that the ``ColumnElement`` may be associated with a ``Selectable`` which was derived from another ``Selectable``. An example of a "derived" ``Selectable`` is an ``Alias`` of a ``Table``. a ``ColumnElement``, by subclassing the ``_CompareMixin`` mixin class, provides the ability to generate new ``ClauseElement`` objects using Python expressions. See the ``_CompareMixin`` docstring for more details. """ primary_key = property(lambda self:getattr(self, '_primary_key', False), doc=\ """Primary key flag. Indicates if this ``Column`` represents part or whole of a primary key for its parent table. """) foreign_keys = property(lambda self:getattr(self, '_foreign_keys', []), doc=\ """Foreign key accessor. References a list of ``ForeignKey`` objects which each represent a foreign key placed on this column's ultimate ancestor. """) columns = property(lambda self:[self], doc=\ """Columns accessor which returns ``self``, to provide compatibility with ``Selectable`` objects. """) def _one_fkey(self): if len(self._foreign_keys): return list(self._foreign_keys)[0] else: return None foreign_key = property(_one_fkey) def _get_orig_set(self): try: return self.__orig_set except AttributeError: self.__orig_set = util.Set([self]) return self.__orig_set def _set_orig_set(self, s): if len(s) == 0: s.add(self) self.__orig_set = s orig_set = property(_get_orig_set, _set_orig_set, doc=\ """A Set containing TableClause-bound, non-proxied ColumnElements for which this ColumnElement is a proxy. In all cases except for a column proxied from a Union (i.e. CompoundSelect), this set will be just one element. """) def shares_lineage(self, othercolumn): """Return True if the given ``ColumnElement`` has a common ancestor to this ``ColumnElement``. """ for c in self.orig_set: if c in othercolumn.orig_set: return True else: return False def _make_proxy(self, selectable, name=None): """Create a new ``ColumnElement`` representing this ``ColumnElement`` as it appears in the select list of a descending selectable. The default implementation returns a ``_ColumnClause`` if a name is given, else just returns self. """ if name is not None: co = _ColumnClause(name, selectable) co.orig_set = self.orig_set selectable.columns[name]= co return co else: return self class ColumnCollection(util.OrderedProperties): """An ordered dictionary that stores a list of ColumnElement instances. Overrides the ``__eq__()`` method to produce SQL clauses between sets of correlated columns. """ def __init__(self, *cols): super(ColumnCollection, self).__init__() [self.add(c) for c in cols] def __str__(self): return repr([str(c) for c in self]) def add(self, column): """Add a column to this collection. The key attribute of the column will be used as the hash key for this dictionary. """ # Allow an aliased column to replace an unaliased column of the # same name. if self.has_key(column.name): other = self[column.name] if other.name == other.key: del self[other.name] self[column.key] = column def remove(self, column): del self[column.key] def extend(self, iter): for c in iter: self.add(c) def __eq__(self, other): l = [] for c in other: for local in self: if c.shares_lineage(local): l.append(c==local) return and_(*l) def __contains__(self, col): return self.contains_column(col) def contains_column(self, col): # have to use a Set here, because it will compare the identity # of the column, not just using "==" for comparison which will always return a # "True" value (i.e. a BinaryClause...) return col in util.Set(self) class ColumnSet(util.OrderedSet): def contains_column(self, col): return col in self def extend(self, cols): for col in cols: self.add(col) def __add__(self, other): return list(self) + list(other) def __eq__(self, other): l = [] for c in other: for local in self: if c.shares_lineage(local): l.append(c==local) return and_(*l) class FromClause(Selectable): """Represent an element that can be used within the ``FROM`` clause of a ``SELECT`` statement. """ def __init__(self, name=None): self.name = name def _get_from_objects(self): # this could also be [self], at the moment it doesnt matter to the Select object return [] def default_order_by(self): return [self.oid_column] def accept_visitor(self, visitor): visitor.visit_fromclause(self) def count(self, whereclause=None, **params): if len(self.primary_key): col = list(self.primary_key)[0] else: col = list(self.columns)[0] return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) def join(self, right, *args, **kwargs): return Join(self, right, *args, **kwargs) def outerjoin(self, right, *args, **kwargs): return Join(self, right, isouter=True, *args, **kwargs) def alias(self, name=None): return Alias(self, name) def named_with_column(self): """True if the name of this FromClause may be prepended to a column in a generated SQL statement. """ return False def _locate_oid_column(self): """Subclasses should override this to return an appropriate OID column.""" return None def _get_oid_column(self): if not hasattr(self, '_oid_column'): self._oid_column = self._locate_oid_column() return self._oid_column def _get_all_embedded_columns(self): ret = [] class FindCols(ClauseVisitor): def visit_column(self, col): ret.append(col) FindCols().traverse(self) return ret def corresponding_column(self, column, raiseerr=True, keys_ok=False, require_embedded=False): """Given a ``ColumnElement``, return the exported ``ColumnElement`` object from this ``Selectable`` which corresponds to that original ``Column`` via a common anscestor column. column the target ``ColumnElement`` to be matched raiseerr if True, raise an error if the given ``ColumnElement`` could not be matched. if False, non-matches will return None. keys_ok if the ``ColumnElement`` cannot be matched, attempt to match based on the string "key" property of the column alone. This makes the search much more liberal. require_embedded only return corresponding columns for the given ``ColumnElement``, if the given ``ColumnElement`` is actually present within a sub-element of this ``FromClause``. Normally the column will match if it merely shares a common anscestor with one of the exported columns of this ``FromClause``. """ if column in self.c: return column if require_embedded and column not in util.Set(self._get_all_embedded_columns()): if not raiseerr: return None else: raise exceptions.InvalidRequestError("Column instance '%s' is not directly present within selectable '%s'" % (str(column), column.table)) for c in column.orig_set: try: return self.original_columns[c] except KeyError: pass else: if keys_ok: try: return self.c[column.name] except KeyError: pass if not raiseerr: return None else: raise exceptions.InvalidRequestError("Given column '%s', attached to table '%s', failed to locate a corresponding column from table '%s'" % (str(column), str(getattr(column, 'table', None)), self.name)) def _get_exported_attribute(self, name): try: return getattr(self, name) except AttributeError: self._export_columns() return getattr(self, name) columns = property(lambda s:s._get_exported_attribute('_columns')) c = property(lambda s:s._get_exported_attribute('_columns')) primary_key = property(lambda s:s._get_exported_attribute('_primary_key')) foreign_keys = property(lambda s:s._get_exported_attribute('_foreign_keys')) original_columns = property(lambda s:s._get_exported_attribute('_orig_cols'), doc=\ """A dictionary mapping an original Table-bound column to a proxied column in this FromClause. """) oid_column = property(_get_oid_column) def _export_columns(self, columns=None): """Initialize column collections. The collections include the primary key, foreign keys, list of all columns, as well as the *_orig_cols* collection which is a dictionary used to match Table-bound columns to proxied columns in this ``FromClause``. The columns in each collection are *proxied* from the columns returned by the _exportable_columns method, where a *proxied* column maintains most or all of the properties of its original column, except its parent ``Selectable`` is this ``FromClause``. """ if hasattr(self, '_columns') and columns is None: # TODO: put a mutex here ? this is a key place for threading probs return self._columns = ColumnCollection() self._primary_key = ColumnSet() self._foreign_keys = util.Set() self._orig_cols = {} if columns is None: columns = self._adjusted_exportable_columns() for co in columns: cp = self._proxy_column(co) for ci in cp.orig_set: cx = self._orig_cols.get(ci) # TODO: the '=' thing here relates to the order of columns as they are placed in the # "columns" collection of a CompositeSelect, illustrated in test/sql/selectable.SelectableTest.testunion # make this relationship less brittle if cx is None or cp._distance <= cx._distance: self._orig_cols[ci] = cp if self.oid_column is not None: for ci in self.oid_column.orig_set: self._orig_cols[ci] = self.oid_column def _adjusted_exportable_columns(self): """return the list of ColumnElements represented within this FromClause's _exportable_columns""" export = self._exportable_columns() for column in export: try: s = column._selectable() except AttributeError: continue for co in s.columns: yield co def _exportable_columns(self): return [] def _proxy_column(self, column): return column._make_proxy(self) class _BindParamClause(ClauseElement, _CompareMixin): """Represent a bind parameter. Public constructor is the ``bindparam()`` function. """ def __init__(self, key, value, shortname=None, type=None, unique=False): """Construct a _BindParamClause. key the key for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other ``_BindParamClause`` objects exist with the same key, or if its length is too long and truncation is required. value Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution. shortname Defaults to the key, a *short name* that will also identify this bind parameter, similar to an alias. the bind parameter keys sent to a statement compilation or compiled execution may match either the key or the shortname of the corresponding ``_BindParamClause`` objects. type A ``TypeEngine`` object that will be used to pre-process the value corresponding to this ``_BindParamClause`` at execution time. unique if True, the key name of this BindParamClause will be modified if another ``_BindParamClause`` of the same name already has been located within the containing ``ClauseElement``. """ self.key = key self.value = value self.shortname = shortname or key self.unique = unique self.type = sqltypes.to_instance(type) def accept_visitor(self, visitor): visitor.visit_bindparam(self) def _get_from_objects(self): return [] def copy_container(self): return _BindParamClause(self.key, self.value, self.shortname, self.type, unique=self.unique) def typeprocess(self, value, dialect): return self.type.dialect_impl(dialect).convert_bind_param(value, dialect) def compare(self, other): """Compare this ``_BindParamClause`` to the given clause. Since ``compare()`` is meant to compare statement syntax, this method returns True if the two ``_BindParamClauses`` have just the same type. """ return isinstance(other, _BindParamClause) and other.type.__class__ == self.type.__class__ def __repr__(self): return "_BindParamClause(%s, %s, type=%s)" % (repr(self.key), repr(self.value), repr(self.type)) class _TypeClause(ClauseElement): """Handle a type keyword in a SQL statement. Used by the ``Case`` statement. """ def __init__(self, type): self.type = type def accept_visitor(self, visitor): visitor.visit_typeclause(self) def _get_from_objects(self): return [] class _TextClause(ClauseElement): """Represent a literal SQL text fragment. Public constructor is the ``text()`` function. """ def __init__(self, text = "", bind=None, engine=None, bindparams=None, typemap=None): self._bind = bind or engine self.bindparams = {} self.typemap = typemap if typemap is not None: for key in typemap.keys(): typemap[key] = sqltypes.to_instance(typemap[key]) def repl(m): self.bindparams[m.group(1)] = bindparam(m.group(1)) return ":%s" % m.group(1) # scan the string and search for bind parameter names, add them # to the list of bindparams self.text = re.compile(r'(? RIGHT``.""" def __init__(self, left, right, operator, type=None, negate=None): self.left = _literals_as_text(left).self_group(against=operator) self.right = _literals_as_text(right).self_group(against=operator) self.operator = operator self.type = sqltypes.to_instance(type) self.negate = negate def copy_container(self): return self.__class__(self.left.copy_container(), self.right.copy_container(), self.operator) def _get_from_objects(self): return self.left._get_from_objects() + self.right._get_from_objects() def get_children(self, **kwargs): return self.left, self.right def accept_visitor(self, visitor): visitor.visit_binary(self) def compare(self, other): """Compare this ``_BinaryExpression`` against the given ``_BinaryExpression``.""" return ( isinstance(other, _BinaryExpression) and self.operator == other.operator and ( self.left.compare(other.left) and self.right.compare(other.right) or ( self.operator in ['=', '!=', '+', '*'] and self.left.compare(other.right) and self.right.compare(other.left) ) ) ) def self_group(self, against=None): # use small/large defaults for comparison so that unknown operators are always parenthesized if self.operator != against and (PRECEDENCE.get(self.operator, PRECEDENCE['_smallest']) <= PRECEDENCE.get(against, PRECEDENCE['_largest'])): return _Grouping(self) else: return self def _negate(self): if self.negate is not None: return _BinaryExpression(self.left, self.right, self.negate, negate=self.operator, type=self.type) else: return super(_BinaryExpression, self)._negate() class _Exists(_UnaryExpression): def __init__(self, *args, **kwargs): kwargs['correlate'] = True s = select(*args, **kwargs).self_group() _UnaryExpression.__init__(self, s, operator="EXISTS") def _hide_froms(self): return self._get_from_objects() class Join(FromClause): """represent a ``JOIN`` construct between two ``FromClause`` elements. the public constructor function for ``Join`` is the module-level ``join()`` function, as well as the ``join()`` method available off all ``FromClause`` subclasses. """ def __init__(self, left, right, onclause=None, isouter = False): self.left = left._selectable() self.right = right._selectable() if onclause is None: self.onclause = self._match_primaries(self.left, self.right) else: self.onclause = onclause self.isouter = isouter self.__folded_equivalents = None self._init_primary_key() name = property(lambda s: "Join object on " + s.left.name + " " + s.right.name) encodedname = property(lambda s: s.name.encode('ascii', 'backslashreplace')) def _init_primary_key(self): from sqlalchemy import schema pkcol = util.Set([c for c in self._adjusted_exportable_columns() if c.primary_key]) equivs = {} def add_equiv(a, b): for x, y in ((a, b), (b, a)): if x in equivs: equivs[x].add(y) else: equivs[x] = util.Set([y]) class BinaryVisitor(ClauseVisitor): def visit_binary(self, binary): if binary.operator == '=' and isinstance(binary.left, schema.Column) and isinstance(binary.right, schema.Column): add_equiv(binary.left, binary.right) BinaryVisitor().traverse(self.onclause) for col in pkcol: for fk in col.foreign_keys: if fk.column in pkcol: add_equiv(col, fk.column) omit = util.Set() for col in pkcol: p = col for c in equivs.get(col, util.Set()): if p.references(c) or (c.primary_key and not p.primary_key): omit.add(p) p = c self.__primary_key = ColumnSet([c for c in self._adjusted_exportable_columns() if c.primary_key and c not in omit]) primary_key = property(lambda s:s.__primary_key) def _locate_oid_column(self): return self.left.oid_column def _exportable_columns(self): return [c for c in self.left.columns] + [c for c in self.right.columns] def _proxy_column(self, column): self._columns[column._label] = column for f in column.foreign_keys: self._foreign_keys.add(f) return column def _match_primaries(self, primary, secondary): crit = [] constraints = util.Set() for fk in secondary.foreign_keys: if fk.references(primary): crit.append(primary.corresponding_column(fk.column) == fk.parent) constraints.add(fk.constraint) self.foreignkey = fk.parent if primary is not secondary: for fk in primary.foreign_keys: if fk.references(secondary): crit.append(secondary.corresponding_column(fk.column) == fk.parent) constraints.add(fk.constraint) self.foreignkey = fk.parent if len(crit) == 0: raise exceptions.ArgumentError("Can't find any foreign key relationships " "between '%s' and '%s'" % (primary.name, secondary.name)) elif len(constraints) > 1: raise exceptions.ArgumentError("Can't determine join between '%s' and '%s'; " "tables have more than one foreign key " "constraint relationship between them. " "Please specify the 'onclause' of this " "join explicitly." % (primary.name, secondary.name)) elif len(crit) == 1: return (crit[0]) else: return and_(*crit) def _group_parenthesized(self): return True def _get_folded_equivalents(self, equivs=None): if self.__folded_equivalents is not None: return self.__folded_equivalents if equivs is None: equivs = util.Set() class LocateEquivs(NoColumnVisitor): def visit_binary(self, binary): if binary.operator == '=' and binary.left.name == binary.right.name: equivs.add(binary.right) equivs.add(binary.left) LocateEquivs().traverse(self.onclause) collist = [] if isinstance(self.left, Join): left = self.left._get_folded_equivalents(equivs) else: left = list(self.left.columns) if isinstance(self.right, Join): right = self.right._get_folded_equivalents(equivs) else: right = list(self.right.columns) used = util.Set() for c in left + right: if c in equivs: if c.name not in used: collist.append(c) used.add(c.name) else: collist.append(c) self.__folded_equivalents = collist return self.__folded_equivalents folded_equivalents = property(_get_folded_equivalents, doc="Returns the column list of this Join with all equivalently-named, " "equated columns folded into one column, where 'equated' means they are " "equated to each other in the ON clause of this join.") def select(self, whereclause = None, fold_equivalents=False, **kwargs): """Create a ``Select`` from this ``Join``. whereclause the WHERE criterion that will be sent to the ``select()`` function fold_equivalents based on the join criterion of this ``Join``, do not include repeat column names in the column list of the resulting select, for columns that are calculated to be "equivalent" based on the join criterion of this ``Join``. this will recursively apply to any joins directly nested by this one as well. \**kwargs all other kwargs are sent to the underlying ``select()`` function. See the ``select()`` module level function for details. """ if fold_equivalents: collist = self.folded_equivalents else: collist = [self.left, self.right] return select(collist, whereclause, from_obj=[self], **kwargs) def get_children(self, **kwargs): return self.left, self.right, self.onclause def accept_visitor(self, visitor): visitor.visit_join(self) engine = property(lambda s:s.left.engine or s.right.engine) def alias(self, name=None): """Create a ``Select`` out of this ``Join`` clause and return an ``Alias`` of it. The ``Select`` is not correlating. """ return self.select(use_labels=True, correlate=False).alias(name) def _hide_froms(self): return self.left._get_from_objects() + self.right._get_from_objects() def _get_from_objects(self): return [self] + self.onclause._get_from_objects() + self.left._get_from_objects() + self.right._get_from_objects() class Alias(FromClause): """represent an alias, as typically applied to any table or sub-select within a SQL statement using the ``AS`` keyword (or without the keyword on certain databases such as Oracle). this object is constructed from the ``alias()`` module level function as well as the ``alias()`` method available on all ``FromClause`` subclasses. """ def __init__(self, selectable, alias=None): baseselectable = selectable while isinstance(baseselectable, Alias): baseselectable = baseselectable.selectable self.original = baseselectable self.selectable = selectable if alias is None: if self.original.named_with_column(): alias = getattr(self.original, 'name', None) if alias is None: alias = 'anon' elif len(alias) > 15: alias = alias[0:15] alias = alias + "_" + hex(random.randint(0, 65535))[2:] self.name = alias self.encodedname = alias.encode('ascii', 'backslashreplace') self.case_sensitive = getattr(baseselectable, "case_sensitive", True) def supports_execution(self): return self.original.supports_execution() def _locate_oid_column(self): if self.selectable.oid_column is not None: return self.selectable.oid_column._make_proxy(self) else: return None def named_with_column(self): return True def _exportable_columns(self): #return self.selectable._exportable_columns() return self.selectable.columns def get_children(self, **kwargs): for c in self.c: yield c yield self.selectable def accept_visitor(self, visitor): visitor.visit_alias(self) def _get_from_objects(self): return [self] def _group_parenthesized(self): return False bind = property(lambda s: s.selectable.bind) engine = bind class _Grouping(ColumnElement): def __init__(self, elem): self.elem = elem self.type = getattr(elem, 'type', None) key = property(lambda s: s.elem.key) _label = property(lambda s: s.elem._label) orig_set = property(lambda s:s.elem.orig_set) def copy_container(self): return _Grouping(self.elem.copy_container()) def accept_visitor(self, visitor): visitor.visit_grouping(self) def get_children(self, **kwargs): return self.elem, def _hide_froms(self): return self.elem._hide_froms() def _get_from_objects(self): return self.elem._get_from_objects() def __getattr__(self, attr): return getattr(self.elem, attr) class _Label(ColumnElement): """represent a label, as typically applied to any column-level element using the ``AS`` sql keyword. this object is constructed from the ``label()`` module level function as well as the ``label()`` method available on all ``ColumnElement`` subclasses. """ def __init__(self, name, obj, type=None): self.name = name while isinstance(obj, _Label): obj = obj.obj self.obj = obj.self_group(against='AS') self.case_sensitive = getattr(obj, "case_sensitive", True) self.type = sqltypes.to_instance(type or getattr(obj, 'type', None)) key = property(lambda s: s.name) _label = property(lambda s: s.name) orig_set = property(lambda s:s.obj.orig_set) def _compare_self(self): return self.obj def get_children(self, **kwargs): return self.obj, def accept_visitor(self, visitor): visitor.visit_label(self) def _get_from_objects(self): return self.obj._get_from_objects() def _hide_froms(self): return self.obj._hide_froms() def _make_proxy(self, selectable, name = None): if isinstance(self.obj, Selectable): return self.obj._make_proxy(selectable, name=self.name) else: return column(self.name)._make_proxy(selectable=selectable) legal_characters = util.Set(string.ascii_letters + string.digits + '_') class _ColumnClause(ColumnElement): """Represents a generic column expression from any textual string. This includes columns associated with tables, aliases and select statements, but also any arbitrary text. May or may not be bound to an underlying ``Selectable``. ``_ColumnClause`` is usually created publically via the ``column()`` function or the ``column_literal()`` function. text the text of the element. selectable parent selectable. type ``TypeEngine`` object which can associate this ``_ColumnClause`` with a type. case_sensitive defines whether identifier quoting rules will be applied to the generated text of this ``_ColumnClause`` so that it is identified in a case-sensitive manner. is_literal if True, the ``_ColumnClause`` is assumed to be an exact expression that will be delivered to the output with no quoting rules applied regardless of case sensitive settings. the ``column_literal()`` function is usually used to create such a ``_ColumnClause``. """ def __init__(self, text, selectable=None, type=None, _is_oid=False, case_sensitive=True, is_literal=False): self.key = self.name = text self.encodedname = isinstance(self.name, unicode) and self.name.encode('ascii', 'backslashreplace') or self.name self.table = selectable self.type = sqltypes.to_instance(type) self._is_oid = _is_oid self._distance = 0 self.__label = None self.case_sensitive = case_sensitive self.is_literal = is_literal def _get_label(self): """Generate a 'label' for this column. The label is a product of the parent table name and column name, and is treated as a unique identifier of this ``Column`` across all ``Tables`` and derived selectables for a particular metadata collection. """ # for a "literal" column, we've no idea what the text is # therefore no 'label' can be automatically generated if self.is_literal: return None if self.__label is None: if self.table is not None and self.table.named_with_column(): self.__label = self.table.name + "_" + self.name counter = 1 while self.table.c.has_key(self.__label): self.__label = self.__label + "_%d" % counter counter += 1 else: self.__label = self.name self.__label = "".join([x for x in self.__label if x in legal_characters]) return self.__label is_labeled = property(lambda self:self.name != list(self.orig_set)[0].name) _label = property(_get_label) def label(self, name): # if going off the "__label" property and its None, we have # no label; return self if name is None: return self else: return super(_ColumnClause, self).label(name) def accept_visitor(self, visitor): visitor.visit_column(self) def _get_from_objects(self): if self.table is not None: return [self.table] else: return [] def _bind_param(self, obj): return _BindParamClause(self._label, obj, shortname = self.name, type=self.type, unique=True) def _make_proxy(self, selectable, name = None): # propigate the "is_literal" flag only if we are keeping our name, # otherwise its considered to be a label is_literal = self.is_literal and (name is None or name == self.name) c = _ColumnClause(name or self.name, selectable=selectable, _is_oid=self._is_oid, type=self.type, is_literal=is_literal) c.orig_set = self.orig_set c._distance = self._distance + 1 if not self._is_oid: selectable.columns[c.name] = c return c def _compare_type(self, obj): return self.type def _group_parenthesized(self): return False class TableClause(FromClause): """represents a "table" construct. Note that this represents tables only as another syntactical construct within SQL expressions; it does not provide schema-level functionality. """ def __init__(self, name, *columns): super(TableClause, self).__init__(name) self.name = self.fullname = name self.encodedname = self.name.encode('ascii', 'backslashreplace') self._oid_column = _ColumnClause('oid', self, _is_oid=True) self._export_columns(columns) def named_with_column(self): return True def append_column(self, c): self._columns[c.name] = c c.table = self def _locate_oid_column(self): return self._oid_column def _proxy_column(self, c): self.append_column(c) return c def _orig_columns(self): try: return self._orig_cols except AttributeError: self._orig_cols= {} for c in self.columns: for ci in c.orig_set: self._orig_cols[ci] = c return self._orig_cols original_columns = property(_orig_columns) def get_children(self, column_collections=True, **kwargs): if column_collections: return [c for c in self.c] else: return [] def accept_visitor(self, visitor): visitor.visit_table(self) def _exportable_columns(self): raise NotImplementedError() def _group_parenthesized(self): return False def count(self, whereclause=None, **params): if len(self.primary_key): col = list(self.primary_key)[0] else: col = list(self.columns)[0] return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) def join(self, right, *args, **kwargs): return Join(self, right, *args, **kwargs) def outerjoin(self, right, *args, **kwargs): return Join(self, right, isouter = True, *args, **kwargs) def alias(self, name=None): return Alias(self, name) def select(self, whereclause = None, **params): return select([self], whereclause, **params) def insert(self, values = None): return insert(self, values=values) def update(self, whereclause = None, values = None): return update(self, whereclause, values) def delete(self, whereclause = None): return delete(self, whereclause) def _get_from_objects(self): return [self] class _SelectBaseMixin(object): """Base class for ``Select`` and ``CompoundSelects``.""" def supports_execution(self): return True def order_by(self, *clauses): if len(clauses) == 1 and clauses[0] is None: self.order_by_clause = ClauseList() elif getattr(self, 'order_by_clause', None): self.order_by_clause = ClauseList(*(list(self.order_by_clause.clauses) + list(clauses))) else: self.order_by_clause = ClauseList(*clauses) def group_by(self, *clauses): if len(clauses) == 1 and clauses[0] is None: self.group_by_clause = ClauseList() elif getattr(self, 'group_by_clause', None): self.group_by_clause = ClauseList(*(list(clauses)+list(self.group_by_clause.clauses))) else: self.group_by_clause = ClauseList(*clauses) def select(self, whereclauses = None, **params): return select([self], whereclauses, **params) def _get_from_objects(self): if self.is_where or self.is_scalar: return [] else: return [self] class CompoundSelect(_SelectBaseMixin, FromClause): def __init__(self, keyword, *selects, **kwargs): _SelectBaseMixin.__init__(self) self.keyword = keyword self.use_labels = kwargs.pop('use_labels', False) self.should_correlate = kwargs.pop('correlate', False) self.for_update = kwargs.pop('for_update', False) self.nowait = kwargs.pop('nowait', False) self.limit = kwargs.pop('limit', None) self.offset = kwargs.pop('offset', None) self.is_compound = True self.is_where = False self.is_scalar = False self.is_subquery = False # unions group from left to right, so don't group first select self.selects = [n and select.self_group(self) or select for n,select in enumerate(selects)] # some DBs do not like ORDER BY in the inner queries of a UNION, etc. for s in selects: s.order_by(None) self.group_by(*kwargs.pop('group_by', [None])) self.order_by(*kwargs.pop('order_by', [None])) if len(kwargs): raise TypeError("invalid keyword argument(s) for CompoundSelect: %s" % repr(kwargs.keys())) self._col_map = {} name = property(lambda s:s.keyword + " statement") def self_group(self, against=None): return _Grouping(self) def _locate_oid_column(self): return self.selects[0].oid_column def _exportable_columns(self): for s in self.selects: for c in s.c: yield c def _proxy_column(self, column): if self.use_labels: col = column._make_proxy(self, name=column._label) else: col = column._make_proxy(self) try: colset = self._col_map[col.name] except KeyError: colset = util.Set() self._col_map[col.name] = colset [colset.add(c) for c in col.orig_set] col.orig_set = colset return col def get_children(self, column_collections=True, **kwargs): return (column_collections and list(self.c) or []) + \ [self.order_by_clause, self.group_by_clause] + list(self.selects) def accept_visitor(self, visitor): visitor.visit_compound_select(self) def _find_engine(self): for s in self.selects: e = s._find_engine() if e: return e else: return None class Select(_SelectBaseMixin, FromClause): """Represent a ``SELECT`` statement, with appendable clauses, as well as the ability to execute itself and return a result set. """ def __init__(self, columns=None, whereclause=None, from_obj=[], order_by=None, group_by=None, having=None, use_labels=False, distinct=False, for_update=False, engine=None, bind=None, limit=None, offset=None, scalar=False, correlate=True): """construct a Select object. The public constructor for Select is the [sqlalchemy.sql#select()] function; see that function for argument descriptions. """ _SelectBaseMixin.__init__(self) self.__froms = util.OrderedSet() self.__hide_froms = util.Set([self]) self.use_labels = use_labels self.whereclause = None self.having = None self._bind = bind or engine self.limit = limit self.offset = offset self.for_update = for_update self.is_compound = False # indicates that this select statement should not expand its columns # into the column clause of an enclosing select, and should instead # act like a single scalar column self.is_scalar = scalar if scalar: # allow corresponding_column to return None self.orig_set = util.Set() # indicates if this select statement, as a subquery, should automatically correlate # its FROM clause to that of an enclosing select, update, or delete statement. # note that the "correlate" method can be used to explicitly add a value to be correlated. self.should_correlate = correlate # indicates if this select statement is a subquery inside another query self.is_subquery = False # indicates if this select statement is in the from clause of another query self.is_selected_from = False # indicates if this select statement is a subquery as a criterion # inside of a WHERE clause self.is_where = False self.distinct = distinct self._raw_columns = [] self.__correlated = {} self.__correlator = Select._CorrelatedVisitor(self, False) self.__wherecorrelator = Select._CorrelatedVisitor(self, True) self.__fromvisitor = Select._FromVisitor(self) self.order_by_clause = self.group_by_clause = None if columns is not None: for c in columns: self.append_column(c) if order_by: order_by = util.to_list(order_by) if group_by: group_by = util.to_list(group_by) self.order_by(*(order_by or [None])) self.group_by(*(group_by or [None])) for c in self.order_by_clause: self.__correlator.traverse(c) for c in self.group_by_clause: self.__correlator.traverse(c) for f in from_obj: self.append_from(f) # whereclauses must be appended after the columns/FROM, since it affects # the correlation of subqueries. see test/sql/select.py SelectTest.testwheresubquery if whereclause is not None: self.append_whereclause(whereclause) if having is not None: self.append_having(having) class _CorrelatedVisitor(NoColumnVisitor): """Visit a clause, locate any ``Select`` clauses, and tell them that they should correlate their ``FROM`` list to that of their parent. """ def __init__(self, select, is_where): NoColumnVisitor.__init__(self) self.select = select self.is_where = is_where def visit_compound_select(self, cs): self.visit_select(cs) def visit_column(self, c): pass def visit_table(self, c): pass def visit_select(self, select): if select is self.select: return select.is_where = self.is_where select.is_subquery = True if not select.should_correlate: return [select.correlate(x) for x in self.select._Select__froms] class _FromVisitor(NoColumnVisitor): def __init__(self, select): NoColumnVisitor.__init__(self) self.select = select def visit_select(self, select): if select is self.select: return select.is_selected_from = True select.is_subquery = True def append_column(self, column): if _is_literal(column): column = literal_column(str(column)) if isinstance(column, Select) and column.is_scalar: column = column.self_group(against=',') self._raw_columns.append(column) if self.is_scalar and not hasattr(self, 'type'): self.type = column.type # if the column is a Select statement itself, # accept visitor self.__correlator.traverse(column) # visit the FROM objects of the column looking for more Selects for f in column._get_from_objects(): if f is not self: self.__correlator.traverse(f) self._process_froms(column, False) def _make_proxy(self, selectable, name): if self.is_scalar: return self._raw_columns[0]._make_proxy(selectable, name) else: raise exceptions.InvalidRequestError("Not a scalar select statement") def label(self, name): if not self.is_scalar: raise exceptions.InvalidRequestError("Not a scalar select statement") else: return label(name, self) def _exportable_columns(self): return [c for c in self._raw_columns if isinstance(c, Selectable)] def _proxy_column(self, column): if self.use_labels: return column._make_proxy(self, name=column._label) else: return column._make_proxy(self) def _process_froms(self, elem, asfrom): for f in elem._get_from_objects(): self.__fromvisitor.traverse(f) self.__froms.add(f) if asfrom: self.__froms.add(elem) for f in elem._hide_froms(): self.__hide_froms.add(f) def self_group(self, against=None): if isinstance(against, CompoundSelect): return self return _Grouping(self) def append_whereclause(self, whereclause): self._append_condition('whereclause', whereclause) def append_having(self, having): self._append_condition('having', having) def _append_condition(self, attribute, condition): if isinstance(condition, basestring): condition = _TextClause(condition) self.__wherecorrelator.traverse(condition) self._process_froms(condition, False) if getattr(self, attribute) is not None: setattr(self, attribute, and_(getattr(self, attribute), condition)) else: setattr(self, attribute, condition) def correlate(self, from_obj): """Given a ``FROM`` object, correlate this ``SELECT`` statement to it. This basically means the given from object will not come out in this select statement's ``FROM`` clause when printed. """ self.__correlated[from_obj] = from_obj def append_from(self, fromclause): if isinstance(fromclause, basestring): fromclause = FromClause(fromclause) self.__correlator.traverse(fromclause) self._process_froms(fromclause, True) def _locate_oid_column(self): for f in self.__froms: if f is self: # we might be in our own _froms list if a column with us as the parent is attached, # which includes textual columns. continue oid = f.oid_column if oid is not None: return oid else: return None def _calc_froms(self): f = self.__froms.difference(self.__hide_froms) if (len(f) > 1): return f.difference(self.__correlated) else: return f froms = property(_calc_froms, doc="""A collection containing all elements of the ``FROM`` clause.""") def get_children(self, column_collections=True, **kwargs): return (column_collections and list(self.columns) or []) + \ list(self.froms) + \ [x for x in (self.whereclause, self.having, self.order_by_clause, self.group_by_clause) if x is not None] def accept_visitor(self, visitor): visitor.visit_select(self) def union(self, other, **kwargs): return union(self, other, **kwargs) def union_all(self, other, **kwargs): return union_all(self, other, **kwargs) def _find_engine(self): """Try to return a Engine, either explicitly set in this object, or searched within the from clauses for one. """ if self._bind is not None: return self._bind for f in self.__froms: if f is self: continue e = f.bind if e is not None: self._bind = e return e # look through the columns (largely synomous with looking # through the FROMs except in the case of _CalculatedClause/_Function) for cc in self._exportable_columns(): for c in cc.columns: if getattr(c, 'table', None) is self: continue e = c.bind if e is not None: self._bind = e return e return None class _UpdateBase(ClauseElement): """Form the base for ``INSERT``, ``UPDATE``, and ``DELETE`` statements.""" def supports_execution(self): return True class _SelectCorrelator(NoColumnVisitor): def __init__(self, table): NoColumnVisitor.__init__(self) self.table = table def visit_select(self, select): if select.should_correlate: select.correlate(self.table) def _process_whereclause(self, whereclause): if whereclause is not None: _UpdateBase._SelectCorrelator(self.table).traverse(whereclause) return whereclause def _process_colparams(self, parameters): """Receive the *values* of an ``INSERT`` or ``UPDATE`` statement and construct appropriate bind parameters. """ if parameters is None: return None if isinstance(parameters, list) or isinstance(parameters, tuple): pp = {} i = 0 for c in self.table.c: pp[c.key] = parameters[i] i +=1 parameters = pp correlator = _UpdateBase._SelectCorrelator(self.table) for key in parameters.keys(): value = parameters[key] if isinstance(value, ClauseElement): correlator.traverse(value) elif _is_literal(value): if _is_literal(key): col = self.table.c[key] else: col = key try: parameters[key] = bindparam(col, value, unique=True) except KeyError: del parameters[key] return parameters def _find_engine(self): return self.table.bind class _Insert(_UpdateBase): def __init__(self, table, values=None): self.table = table self.select = None self.parameters = self._process_colparams(values) def get_children(self, **kwargs): if self.select is not None: return self.select, else: return () def accept_visitor(self, visitor): visitor.visit_insert(self) class _Update(_UpdateBase): def __init__(self, table, whereclause, values=None): self.table = table self.whereclause = self._process_whereclause(whereclause) self.parameters = self._process_colparams(values) def get_children(self, **kwargs): if self.whereclause is not None: return self.whereclause, else: return () def accept_visitor(self, visitor): visitor.visit_update(self) class _Delete(_UpdateBase): def __init__(self, table, whereclause): self.table = table self.whereclause = self._process_whereclause(whereclause) def get_children(self, **kwargs): if self.whereclause is not None: return self.whereclause, else: return () def accept_visitor(self, visitor): visitor.visit_delete(self)