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import warnings
import cx_Oracle
from django.db.backends.base.introspection import (
BaseDatabaseIntrospection, FieldInfo, TableInfo,
)
from django.utils.deprecation import RemovedInDjango21Warning
from django.utils.encoding import force_text
class DatabaseIntrospection(BaseDatabaseIntrospection):
# Maps type objects to Django Field types.
data_types_reverse = {
cx_Oracle.BLOB: 'BinaryField',
cx_Oracle.CLOB: 'TextField',
cx_Oracle.DATETIME: 'DateField',
cx_Oracle.FIXED_CHAR: 'CharField',
cx_Oracle.FIXED_NCHAR: 'CharField',
cx_Oracle.NATIVE_FLOAT: 'FloatField',
cx_Oracle.NCHAR: 'CharField',
cx_Oracle.NCLOB: 'TextField',
cx_Oracle.NUMBER: 'DecimalField',
cx_Oracle.STRING: 'CharField',
cx_Oracle.TIMESTAMP: 'DateTimeField',
}
cache_bust_counter = 1
def get_field_type(self, data_type, description):
# If it's a NUMBER with scale == 0, consider it an IntegerField
if data_type == cx_Oracle.NUMBER:
precision, scale = description[4:6]
if scale == 0:
if precision > 11:
return 'BigIntegerField'
elif precision == 1:
return 'BooleanField'
else:
return 'IntegerField'
elif scale == -127:
return 'FloatField'
return super(DatabaseIntrospection, self).get_field_type(data_type, description)
def get_table_list(self, cursor):
"""
Returns a list of table and view names in the current database.
"""
cursor.execute("SELECT TABLE_NAME, 't' FROM USER_TABLES UNION ALL "
"SELECT VIEW_NAME, 'v' FROM USER_VIEWS")
return [TableInfo(row[0].lower(), row[1]) for row in cursor.fetchall()]
def get_table_description(self, cursor, table_name):
"Returns a description of the table, with the DB-API cursor.description interface."
# user_tab_columns gives data default for columns
cursor.execute("""
SELECT
column_name,
data_default,
CASE
WHEN char_used IS NULL THEN data_length
ELSE char_length
END as internal_size
FROM user_tab_cols
WHERE table_name = UPPER(%s)""", [table_name])
field_map = {
column: (internal_size, default if default != 'NULL' else None)
for column, default, internal_size in cursor.fetchall()
}
self.cache_bust_counter += 1
cursor.execute("SELECT * FROM {} WHERE ROWNUM < 2 AND {} > 0".format(
self.connection.ops.quote_name(table_name),
self.cache_bust_counter))
description = []
for desc in cursor.description:
name = force_text(desc[0]) # cx_Oracle always returns a 'str' on both Python 2 and 3
internal_size, default = field_map[name]
name = name % {} # cx_Oracle, for some reason, doubles percent signs.
description.append(FieldInfo(*(
(name.lower(),) +
desc[1:3] +
(internal_size, desc[4] or 0, desc[5] or 0) +
desc[6:] +
(default,)
)))
return description
def table_name_converter(self, name):
"Table name comparison is case insensitive under Oracle"
return name.lower()
def _name_to_index(self, cursor, table_name):
"""
Returns a dictionary of {field_name: field_index} for the given table.
Indexes are 0-based.
"""
return {d[0]: i for i, d in enumerate(self.get_table_description(cursor, table_name))}
def get_relations(self, cursor, table_name):
"""
Returns a dictionary of {field_name: (field_name_other_table, other_table)}
representing all relationships to the given table.
"""
table_name = table_name.upper()
cursor.execute("""
SELECT ta.column_name, tb.table_name, tb.column_name
FROM user_constraints, USER_CONS_COLUMNS ca, USER_CONS_COLUMNS cb,
user_tab_cols ta, user_tab_cols tb
WHERE user_constraints.table_name = %s AND
ta.table_name = user_constraints.table_name AND
ta.column_name = ca.column_name AND
ca.table_name = ta.table_name AND
user_constraints.constraint_name = ca.constraint_name AND
user_constraints.r_constraint_name = cb.constraint_name AND
cb.table_name = tb.table_name AND
cb.column_name = tb.column_name AND
ca.position = cb.position""", [table_name])
relations = {}
for row in cursor.fetchall():
relations[row[0].lower()] = (row[2].lower(), row[1].lower())
return relations
def get_key_columns(self, cursor, table_name):
cursor.execute("""
SELECT ccol.column_name, rcol.table_name AS referenced_table, rcol.column_name AS referenced_column
FROM user_constraints c
JOIN user_cons_columns ccol
ON ccol.constraint_name = c.constraint_name
JOIN user_cons_columns rcol
ON rcol.constraint_name = c.r_constraint_name
WHERE c.table_name = %s AND c.constraint_type = 'R'""", [table_name.upper()])
return [tuple(cell.lower() for cell in row)
for row in cursor.fetchall()]
def get_indexes(self, cursor, table_name):
warnings.warn(
"get_indexes() is deprecated in favor of get_constraints().",
RemovedInDjango21Warning, stacklevel=2
)
sql = """
SELECT LOWER(uic1.column_name) AS column_name,
CASE user_constraints.constraint_type
WHEN 'P' THEN 1 ELSE 0
END AS is_primary_key,
CASE user_indexes.uniqueness
WHEN 'UNIQUE' THEN 1 ELSE 0
END AS is_unique
FROM user_constraints, user_indexes, user_ind_columns uic1
WHERE user_constraints.constraint_type (+) = 'P'
AND user_constraints.index_name (+) = uic1.index_name
AND user_indexes.uniqueness (+) = 'UNIQUE'
AND user_indexes.index_name (+) = uic1.index_name
AND uic1.table_name = UPPER(%s)
AND uic1.column_position = 1
AND NOT EXISTS (
SELECT 1
FROM user_ind_columns uic2
WHERE uic2.index_name = uic1.index_name
AND uic2.column_position = 2
)
"""
cursor.execute(sql, [table_name])
indexes = {}
for row in cursor.fetchall():
indexes[row[0]] = {'primary_key': bool(row[1]),
'unique': bool(row[2])}
return indexes
def get_constraints(self, cursor, table_name):
"""
Retrieves any constraints or keys (unique, pk, fk, check, index) across one or more columns.
"""
constraints = {}
# Loop over the constraints, getting PKs, uniques, and checks
cursor.execute("""
SELECT
user_constraints.constraint_name,
LOWER(cols.column_name) AS column_name,
CASE user_constraints.constraint_type
WHEN 'P' THEN 1
ELSE 0
END AS is_primary_key,
CASE
WHEN EXISTS (
SELECT 1
FROM user_indexes
WHERE user_indexes.index_name = user_constraints.index_name
AND user_indexes.uniqueness = 'UNIQUE'
)
THEN 1
ELSE 0
END AS is_unique,
CASE user_constraints.constraint_type
WHEN 'C' THEN 1
ELSE 0
END AS is_check_constraint,
CASE
WHEN user_constraints.constraint_type IN ('P', 'U') THEN 1
ELSE 0
END AS has_index
FROM
user_constraints
LEFT OUTER JOIN
user_cons_columns cols ON user_constraints.constraint_name = cols.constraint_name
WHERE
user_constraints.constraint_type = ANY('P', 'U', 'C')
AND user_constraints.table_name = UPPER(%s)
ORDER BY cols.position
""", [table_name])
for constraint, column, pk, unique, check, index in cursor.fetchall():
# If we're the first column, make the record
if constraint not in constraints:
constraints[constraint] = {
"columns": [],
"primary_key": pk,
"unique": unique,
"foreign_key": None,
"check": check,
"index": index, # All P and U come with index
}
# Record the details
constraints[constraint]['columns'].append(column)
# Foreign key constraints
cursor.execute("""
SELECT
cons.constraint_name,
LOWER(cols.column_name) AS column_name,
LOWER(rcols.table_name),
LOWER(rcols.column_name)
FROM
user_constraints cons
INNER JOIN
user_cons_columns rcols ON rcols.constraint_name = cons.r_constraint_name
LEFT OUTER JOIN
user_cons_columns cols ON cons.constraint_name = cols.constraint_name
WHERE
cons.constraint_type = 'R' AND
cons.table_name = UPPER(%s)
ORDER BY cols.position
""", [table_name])
for constraint, column, other_table, other_column in cursor.fetchall():
# If we're the first column, make the record
if constraint not in constraints:
constraints[constraint] = {
"columns": [],
"primary_key": False,
"unique": False,
"foreign_key": (other_table, other_column),
"check": False,
"index": False,
}
# Record the details
constraints[constraint]['columns'].append(column)
# Now get indexes
cursor.execute("""
SELECT
cols.index_name, LOWER(cols.column_name), cols.descend,
LOWER(ind.index_type)
FROM
user_ind_columns cols, user_indexes ind
WHERE
cols.table_name = UPPER(%s) AND
NOT EXISTS (
SELECT 1
FROM user_constraints cons
WHERE cols.index_name = cons.index_name
) AND cols.index_name = ind.index_name
ORDER BY cols.column_position
""", [table_name])
for constraint, column, order, type_ in cursor.fetchall():
# If we're the first column, make the record
if constraint not in constraints:
constraints[constraint] = {
"columns": [],
"orders": [],
"primary_key": False,
"unique": False,
"foreign_key": None,
"check": False,
"index": True,
"type": 'idx' if type_ == 'normal' else type_,
}
# Record the details
constraints[constraint]['columns'].append(column)
constraints[constraint]['orders'].append(order)
return constraints
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