.. _ref-models:
.. module:: trytond.model

=====
Model
=====

.. class:: Model([id[, \**kwargs]])

This is the base class that every kind of :ref:`model <topics-models>`
inherits. It defines common attributes of all models.

Class attributes are:

.. attribute:: Model.__name__

    It contains the a unique name to reference the model throughout the
    platform.

.. attribute:: Model.__rpc__

    It contains a dictionary with method name as key and an instance of
    :class:`trytond.rpc.RPC` as value.

.. attribute:: Model._error_messages

    It contains a dictionary mapping keywords to an error message. By way of
    example::

        _error_messages = {
            'recursive_categories': 'You can not create recursive categories!',
            'wrong_name': 'You can not use " / " in name field!'
        }

.. attribute:: Model._rec_name

    It contains the name of the field used as name of records. The default
    value is 'name'.

.. attribute:: Model.id

    The definition of the field ``id`` of records.

Class methods:

.. classmethod:: Model.__setup__()

    Setup the class before adding into the :class:`trytond.pool.Pool`.

.. classmethod:: Model.__post_setup__()

    Setup the class after added into the :class:`trytond.pool.Pool`.

.. classmethod:: Model.__register__(module_name)

    Registers the model in ``ir.model`` and ``ir.model.field``.

.. classmethod:: Model.raise_user_error(error[, error_args[, error_description[, error_description_args[, raise_exception]]]])

    Raises an exception that will be displayed as an error message in the
    client.  ``error`` is the key of the error message in ``_error_messages``
    and ``error_args`` is the arguments for the "%"-based substitution of the
    error message.  There is the same parameter for an additional description.
    The boolean ``raise_exception`` can be set to ``False`` to retrieve the
    error message strings.

.. classmethod:: Model.raise_user_warning(warning_name, warning[, warning_args[, warning_description[, warning_description_args]]])

    Raises an exception that will be displayed as a warning message on the
    client, if the user has not yet bypassed it. ``warning_name`` is used to
    uniquely identify the warning. Others parameters are like in
    :meth:`Model.raise_user_error`.

    .. warning::
        It requires that the cursor will be commited as it stores state of the
        warning states by users.
    ..

.. classmethod:: Model.default_get(fields_names[, with_rec_name])

    Returns a dictionary with the default values for each field in
    ``fields_names``. Default values are defined by the returned value of each
    instance method with the pattern ``default_`field_name`()``.
    ``with_rec_name`` allow to add `rec_name` value for each many2one field.

.. classmethod:: Model.fields_get([fields_names])

    Return the definition of each field on the model.

Instance methods:

.. method:: Model.on_change(fieldnames)

    Returns the list of changes by calling `on_change` method of each field.

.. method:: Model.on_change_with(fieldnames)

    Returns the new values of all fields by calling `on_change_with` method of
    each field.

.. method:: Model.pre_validate()

    This method is called by the client to validate the instance.

=========
ModelView
=========

.. class:: ModelView

It adds requirements to display a view of the model in the client.

Class attributes:

.. attribute:: ModelView._buttons

    It contains a dictionary with button name as key and the states dictionary
    for the button. This states dictionary will be used to generate the views
    containing the button.

Static methods:

.. staticmethod:: ModelView.button

    Decorate button method to check group access.

.. staticmethod:: ModelView.button_action(action)

    Same as :meth:`ModelView.button` but return the action id of the XML `id`
    action.

Class methods:

.. classmethod:: ModelView.fields_view_get([view_id[, view_type[, toolbar]]])

    Return a view definition used by the client. The definition is::

        {
            'model': model name,
            'arch': XML description,
            'fields': {
                field name: {
                    ...
                },
            },
            'toolbar': {
                'print': [
                    ...
                ],
                'action': [
                    ...
                ],
                'relate': [
                    ...
                ],
            },
        }

.. classmethod:: ModelView.view_toolbar_get()

    Returns the model specific actions in a dictionary with keys:
        - `print`: a list of available reports
        - `action`: a list of available actions
        - `relate`: a list of available relations

.. classmethod:: ModelView.view_header_get(value[, view_type])

    Returns the window title used by the client for the specific view type.

============
ModelStorage
============

.. class:: ModelStorage

It adds storage capability.

Class attributes are:

.. attribute:: ModelStorage.create_uid

    The definition of the :class:`trytond.model.fields.Many2One` field
    :attr:`create_uid` of records. It contains the :attr:`id` of the user who
    creates the record.

.. attribute:: ModelStorage.create_date

    The definition of the :class:`trytond.model.fields.DateTime` field
    :attr:`create_date` of records.  It contains the datetime of the creation of
    the record.

.. attribute:: ModelStorage.write_uid

    The definition of the :class:`trytond.model.fields.Many2One` field
    :attr:`write_uid` of the records.
    It contains the :attr:`id` of the last user who writes on the record.

.. attribute:: ModelStorage.write_date

    The definition of the :class:`trytond.model.fields.DateTime` field
    :attr:`write_date` of the records. It contains the datetime of the last
    write on the record.

.. attribute:: ModelStorage.rec_name

    The definition of the :class:`trytond.model.fields.Function` field
    :attr:`rec_name`. It is used in the client to display the records with a
    single string.

.. attribute:: ModelStorage._constraints

    .. warning::
        Deprecated, use :class:`trytond.model.ModelStorage.validate` instead.

    The list of constraints that each record must respect. The definition is:

        [ ('function name', 'error keyword'), ... ]

    where ``function name`` is the name of an instance or a class method of the
    which must return a boolean (``False`` when the constraint is violated) and
    ``error keyword`` is a key of :attr:`Model._error_messages`.

Static methods:

.. staticmethod:: ModelStorage.default_create_uid()

    Return the default value for :attr:`create_uid`.

.. staticmethod:: ModelStorage.default_create_date()

    Return the default value for :attr:`create_date`.

CLass methods:

.. classmethod:: ModelStorage.create(vlist)

    Create records. ``vlist`` is list of dictionaries with fields names as key
    and created values as value and return the list of new instances.

.. classmethod:: ModelStorage.trigger_create(records)

    Trigger create actions. It will call actions defined in ``ir.trigger`` if
    ``on_create`` is set and ``condition`` is true.

.. classmethod:: ModelStorage.read(ids[, fields_names])

    Return a list of values for the ids. If ``fields_names`` is set, there will
    be only values for these fields otherwise it will be for all fields.

.. classmethod:: ModelStorage.write(records, values, [[records, values], ...])

    Write ``values`` on the list of records.  ``values`` is a dictionary with
    fields names as key and writen values as value.

.. classmethod:: ModelStorage.trigger_write_get_eligibles(records)

    Return eligible records for write actions by triggers. This dictionary
    is to pass to :meth:`~ModelStorage.trigger_write`.

.. classmethod:: ModelStorage.trigger_write(eligibles)

    Trigger write actions. It will call actions defined in ``ir.trigger`` if
    ``on_write`` is set and ``condition`` was false before
    :meth:`~ModelStorage.write` and true after.

.. classmethod:: ModelStorage.delete(records)

    Delete records.

.. classmethod:: ModelStorage.trigger_delete(records)

    Trigger delete actions. It will call actions defined in ``ir.trigger`` if
    ``on_delete`` is set and ``condition`` is true.

.. classmethod:: ModelStorage.copy(records[, default])

    Duplicate the records. ``default`` is a dictionary of default value for the
    created records.

.. classmethod:: ModelStorage.search(domain[, offset[, limit[, order[, count]]]])

    Return a list of records that match the :ref:`domain <topics-domain>`.

.. classmethod:: ModelStorage.search_count(domain)

    Return the number of records that match the :ref:`domain <topics-domain>`.

.. classmethod:: ModelStorage.search_read(domain[, offset[, limit[, order[, fields_names]]]])

    Call :meth:`search` and :meth:`read` at once.
    Useful for the client to reduce the number of calls.

.. classmethod:: ModelStorage.search_rec_name(name, clause)

    Searcher for the :class:`trytond.model.fields.Function` field
    :attr:`rec_name`.

.. classmethod:: ModelStorage.search_global(cls, text)

    Yield tuples (id, rec_name, icon) for records matching text.
    It is used for the global search.

.. classmethod:: ModelStorage.browse(ids)

    Return a list of record instance for the ``ids``.

.. classmethod:: ModelStorage.export_data(records, fields_names)

    Return a list of list of values for each ``records``.
    The list of values follows ``fields_names``.
    Relational fields are defined with ``/`` at any depth.
    Descriptor on fields are available by appending ``.`` and the name of the
    method on the field that returns the descriptor.

.. classmethod:: ModelStorage.import_data(fields_names, data)

    Create records for all values in ``datas``.
    The field names of values must be defined in ``fields_names``.
    It returns a tuple containing: the number of records imported, the last values
    if failed, the exception if failed and the warning if failed.

.. classmethod:: ModelStorage.check_xml_record(records, values)

    Verify if the records are originating from XML data. It is used to prevent
    modification of data coming from XML files. This method must be overiden to
    change this behavior.

.. classmethod:: ModelStorage.check_recursion(records[, parent])

    Helper method that checks if there is no recursion in the tree composed
    with ``parent`` as parent field name.

.. classmethod:: ModelStorage.validate(records)

    Validate the integrity of records after creation and modification. This
    method must be overridden to add validation and must raise an exception if
    validation fails.

Instance methods:

.. method:: ModelStorage.get_rec_name(name)

    Getter for the :class:`trytond.model.fields.Function` field
    :attr:`rec_name`.

.. method:: ModelStorage.save()

    Save the modification made on the record instance.

========
ModelSQL
========

.. class:: ModelSQL

It implements :class:`ModelStorage` for an SQL database.

Class attributes are:

.. attribute:: ModelSQL._table

    The name of the database table which is mapped to the class.
    If not set, the value of :attr:`Model._name` is used with dots converted to
    underscores.

.. attribute:: ModelSQL._order

    A list of tuples defining the default order of the records:

        [ ('field name', 'ASC'), ('other field name', 'DESC'), ... ]

    where the first element of the tuple is a field name of the model and the
    second is the sort ordering as `ASC` for ascending or `DESC` for
    descending.

.. attribute:: ModelSQL._order_name

    The name of the field (or an SQL statement) on which the records must be
    sorted when sorting on this model from an other model. If not set,
    :attr:`ModelStorage._rec_name` will be used.

.. attribute:: ModelSQL._history

    If true, all changes on records will be stored in a history table.

.. attribute:: ModelSQL._sql_constraints

    A list of SQL constraints that are added on the table:

        [ ('constraint name', 'SQL constraint', 'error message key'), ... ]

    - `constraint name` is the name of the SQL constraint in the database

    - `SQL constraint` is the actual SQL constraint

    - `error message key` is the key of
      :attr:`_sql_error_messages`

.. attribute:: ModelSQL._sql_error_messages

    Like :attr:`Model._error_messages` but for :attr:`_sql_constraints`

Class methods:

.. classmethod:: ModelSQL.__table__()

    Return a SQL Table instance for the Model.

.. classmethod:: ModelSQL.table_query()

    Could be overrided to use a custom SQL query instead of a table of the
    database. It should return a SQL FromItem.

.. classmethod:: ModelSQL.history_revisions(ids)

    Return a sorted list of all revisions for ids. The list is composed of
    the date, id and username of the revision.

.. classmethod:: ModelSQL.restore_history(ids, datetime)

    Restore the record ids from history at the specified date time.
    Restoring a record will still generate an entry in the history table.

    .. warning::
        No access rights are verified and the records are not validated.
    ..

.. classmethod:: ModelStorage.search(domain[, offset[, limit[, order[, count[, query]]]]])

    Return a list of records that match the :ref:`domain <topics-domain>` or
    the sql query if query is True.

.. classmethod:: ModelSQL.search_domain(domain[, active_test])

    Convert a :ref:`domain <topics-domain>` into a tuple containing:

    - a SQL clause string

    - a list of arguments for the SQL clause

    - a list of tables used in the SQL clause

    - a list of arguments for the tables

========
Workflow
========

.. class:: Workflow

A Mix-in class to handle transition check.

Class attribute:

.. attribute:: Workflow._transition_state

    The name of the field that will be used to check state transition.

.. attribute:: Workflow._transitions

    A set containing tuples of from and to state.

Static methods:

.. staticmethod:: Workflow.transition(state)

    Decorate method to filter ids for which the transition is valid and finally
    to update the state of the filtered ids.

==============
ModelSingleton
==============

.. class:: ModelSingleton

Modify :class:`ModelStorage` into a singleton_.
This means that there will be only one record of this model.
It is commonly used to store configuration value.

.. _singleton: http://en.wikipedia.org/wiki/Singleton_pattern

Class methods:

.. classmethod:: ModelSingleton.get_singleton()

    Return the instance of the unique record if there is one.

===============
DictSchemaMixin
===============

.. class:: DictSchemaMixin

A mixin_ for the schema of :class:`trytond.model.fields.Dict` field.

Class attributes are:

.. attribute:: DictSchemaMixin.name

    The definition of the :class:`trytond.model.fields.Char` field for the name
    of the key.

.. attribute:: DictSchemaMixin.string

    The definition of the :class:`trytond.model.fields.Char` field for the
    string of the key.

.. attribute:: DictSchemaMixin.type\_

    The definition of the :class:`trytond.model.fields.Selection` field for the
    type of the key. The available types are:

    * boolean
    * integer
    * char
    * float
    * numeric
    * date
    * datetime
    * selection

.. attribute:: DictSchemaMixin.digits

    The definition of the :class:`trytond.model.fields.Integer` field for the
    digits number when the type is `float` or `numeric`.

.. attribute:: DictSchemaMixin.selection

    The definition of the :class:`trytond.model.fields.Text` field to store the
    couple of key and label when the type is `selection`.
    The format is a key/label separated by ":" per line.

.. attribute:: DictSchemaMixin.selection_sorted

    If the :attr:`selection` must be sorted on label by the client.

.. attribute:: DictSchemaMixin.selection_json

    The definition of the :class:`trytond.model.fields.Function` field to
    return the JSON_ version of the :attr:`selection`.

Static methods:

.. staticmethod:: DictSchemaMixin.default_digits()

    Return the default value for :attr:`digits`.

Class methods:

.. classmethod:: DictSchemaMixin.get_keys(records)

    Return the definition of the keys for the records.

Instance methods:

.. method:: DictSchemaMixin.get_selection_json(name)

    Getter for the :attr:`selection_json`.

==========
MatchMixin
==========

.. class:: MatchMixin

A mixin_ to add to a :class:`Model` a match method on pattern.
The pattern is a dictionary with field name as key and the value to compare.
The record matches the pattern if for all dictionary entries, the value of the
record is equal or not defined.

Instance methods:

.. method:: MatchMixin.match(pattern)

    Return if the instance match the pattern

==========
UnionMixin
==========

.. class:: UnionMixin

A mixin_ to create a :class:`ModelSQL` which is the UNION_ of some
:class:`ModelSQL`'s. The ids of each models are sharded to be unique.

Static methods:

.. staticmethod:: UnionMixin.union_models()

    Return the list of :class:`ModelSQL`'s names

Class methods:

.. classmethod:: UnionMixin.union_shard(column, model)

    Return a SQL expression that shards the column containing record id of
    model name.

.. classmethod:: UnionMixin.union_unshard(record_id)

    Return the original instance of the record for the sharded id.

.. classmethod:: UnionMixin.union_column(name, field, table, Model)

    Return the SQL column that corresponds to the field on the union model.

.. classmethod:: UnionMixin.union_columns(model)

    Return the SQL table and columns to use for the UNION for the model name.


.. _mixin: http://en.wikipedia.org/wiki/Mixin
.. _JSON: http://en.wikipedia.org/wiki/Json
.. _UNION: http://en.wikipedia.org/wiki/Union_(SQL)#UNION_operator