.. _ref-models-fields: .. module:: trytond.model.fields ====== Fields ====== Fields define the behavior of the data on model's record. Field options ============= The following arguments are available to all field types. All are optional except :attr:`Field.string`. ``string`` ---------- .. attribute:: Field.string A string for the label of the field. ``help`` -------- .. attribute:: Field.help A multi-line help string for the field. ``required`` ------------ .. attribute:: Field.required If ``True``, the field is not allowed to be empty. Default is ``False``. ``readonly`` ------------ .. attribute:: Field.readonly If ``True``, the field is not editable in the client. Default is ``False``. .. warning:: For relational fields, it means only the new, delete, add and remove buttons are inactivated. The editable state of the target record must be managed at the target model level. ``domain`` ---------- .. attribute:: Field.domain A :ref:`domain ` constraint that will be applied on the field value. ``states`` ---------- .. attribute:: Field.states A dictionary that defines dynamic states of the field and overrides the static one. Possible keys are ``required``, ``readonly`` and ``invisible``. The values are :class:`~trytond.pyson.PYSON` statements that will be evaluated with the values of the record. ``select`` ---------- .. attribute:: Field.select If true, the content of the field will be indexed. .. _ref-models-fields-on_change: ``on_change`` ------------- .. attribute:: Field.on_change A set of field names. If this attribute is set, the client will call the method ``on_change_`` of the model when the user changes the current field value and will give the values of each fields in this list. The method signature is:: on_change_() This method must change the value of the fields to be updated. .. note:: The on_change_ methods are running in a rollbacked transaction. .. The set of field names could be filled by using the decorator :meth:`depends`. .. _ref-models-fields-on_change_with: ``on_change_with`` ------------------ .. attribute:: Field.on_change_with A set of field names. Same like :attr:`on_change`, but defined the other way around. If this attribute is set, the client will call the method ``on_change_with_`` of the model when the user changes one of the fields defined in the list and will give the values of each fields in this list. The method signature is:: on_change_with_() This method must return the new value of the field. .. note:: The on_change_with_ methods are running in a rollbacked transaction. .. The set of field names could be filled by using the decorator :meth:`depends`. ``depends`` ----------- .. attribute:: Field.depends A list of field names on which the current one depends. This means that the client will also read these fields even if they are not defined on the view. :attr:`Field.depends` is used per example to ensure that :class:`~trytond.pyson.PYSON` statement could be evaluated. ``context`` ----------- .. attribute:: Field.context A dictionary which will update the current context for *relation field*. .. warning:: The context could only depend on direct field of the record and without context. .. ``loading`` ----------- .. attribute:: Field.loading Define how the field must be loaded: ``lazy`` or ``eager``. ``name`` -------- .. attribute:: Field.name The name of the field. Instance methods: .. method:: Field.convert_domain(domain, tables, Model) Convert the simple :ref:`domain ` clause into a SQL expression or a new domain. :ref:`tables ` could be updated to add new joins. .. method:: Field.sql_format(value) Convert the value to use as parameter of SQL queries. .. method:: Field.sql_type() Return the namedtuple('SQLType', 'base type') which defines the SQL type to use for creation and casting. Or `None` if the field is not stored in the database. sql_type is using the `_sql_type` attribute to compute its return value. The backend is responsible for the computation. For the list of supported types by Tryton see :ref:`backend types `. .. method:: Field.sql_column(table) Return the Column instance based on table. .. method:: Field.set_rpc(model) Adds to `model` the default RPC instances required by the field. Default value ============= See :ref:`default value ` Searching ========= A class method could be defined for each field which must return a SQL expression for the given domain instead of the default one. The method signature is:: domain_(domain, tables) Where ``domain`` is the simple :ref:`domain ` clause and ``tables`` is a nested dictionary, see :meth:`~Field.convert_domain`. Ordering ======== A class method could be defined for each field which must return a list of SQL expression on which to order instead of the field. The method signature is:: order_(tables) Where ``tables`` is a nested dictionary, see :meth:`~Field.convert_domain`. Depends ======= .. method:: depends([\*fields[, methods]]) A decorator to define the field names on which the decorated method depends. The `methods` argument can be used to duplicate the field names from other fields. This is usefull if the decorated method calls another method. Field types =========== Boolean ------- .. class:: Boolean(string[, \**options]) A true/false field. Integer ------- .. class:: Integer(string[, \**options]) An integer field. BigInteger ---------- .. class:: BigInteger(string[, \**options]) A long integer field. Char ---- .. class:: Char(string[, size[, translate[, \**options]]]) A single line string field. :class:`Char` has two extra optional arguments: .. attribute:: Char.size The maximum length (in characters) of the field. The size is enforced at the storage level and in the client input. .. attribute:: Char.translate If true, the value of the field is translatable. The value readed and stored will depend on the ``language`` defined in the context. .. attribute:: Char.autocomplete A set of field names. If this attribute is set, the client will call the method ``autocomplete_`` of the model when the user changes one of those field value. The method signature is:: autocomplete_() This method must return a list of string that will populate the ComboboxEntry in the client. The set of field names could be filled by using the decorator :meth:`depends`. Text ---- .. class:: Text(string[, size[, translatable[, \**options]]]) A multi line string field. :class:`Text` has two extra optional arguments: .. attribute:: Text.size Same as :attr:`Char.size` .. attribute:: Text.translate Same as :attr:`Char.translate` Float ----- .. class:: Float(string[, digits[, \**options]]) A floating-point number field. It will be represented in Python by a ``float`` instance. :class:`Float` has one extra optional arguments: .. attribute:: Float.digits A tuple of two integers. The first integer defines the total of numbers in the integer part. The second integer defines the total of numbers in the decimal part. Integers can be replaced by a :class:`~trytond.pyson.PYSON` statement. If digits is None or any values of the tuple is `None`, no validation on the numbers will be done. Numeric ------- .. class:: Numeric(string[, digits[, \**options]]) A fixed-point number field. It will be represented in Python by a ``decimal.Decimal`` instance. :class:`Numeric` has one extra optional arguments: .. attribute:: Numeric.digits Same as :attr:`Float.digits` Date ---- .. class:: Date(string[, \**options]) A date, represented in Python by a ``datetime.date`` instance. DateTime -------- .. class:: DateTime(string[, format, \**options]) A date and time, represented in Python by a ``datetime.datetime`` instance. It is stored in `UTC`_ while displayed in the user timezone. .. _`UTC`: https://en.wikipedia.org/wiki/Coordinated_Universal_Time .. attribute:: DateTime.format A string format as used by strftime. This format will be used to display the time part of the field. The default value is `%H:%M:%S`. The value can be replaced by a :class:`~trytond.pyson.PYSON` statement. Timestamp --------- .. class:: Timestamp(string[, \**options]) A timestamp, represented in Python by a ``datetime.datetime`` instance. Time ---- .. class:: Time(string[, format, \**options]) A time, represented in Python by a ``datetime.time`` instance. .. attribute:: Time.format Same as :attr:`DateTime.format` TimeDelta --------- .. class:: TimeDelta(string[, converter[, \**options]]) An interval, represented in Python by a ``datetime.timedelta`` instance. .. attribute:: TimeDelta.converter The name of the context key containing the time converter. A time converter is a dictionary with the keys: ``s`` (second), ``m`` (minute), ``h`` (hour), ``d`` (day), ``w`` (week), ``M`` (month), ``Y`` (year) and the value in second. Binary ------ .. class:: Binary(string[, \**options]) A binary field. It will be represented in Python by a ``bytes`` instance. .. warning:: If the context contains a key composed of the model name and field name separated by a dot and its value is the string `size` then the read value is the size instead of the content. :class:`Binary` has three extra optional arguments: .. attribute:: Binary.filename Name of the field that holds the data's filename. Default value is an empty string, which means the data has no filename (in this case, the filename is hidden, and the "Open" button is hidden when the widget is set to "image"). .. attribute:: Binary.file_id Name of the field that holds the `FileStore` identifier. Default value is `None` which means the data is stored in the database. The field must be on the same table and accept `char` values. .. warning:: Switching from database to file-store is supported transparently. But switching from file-store to database is not supported without manually upload to the database all the files. .. attribute:: Binary.store_prefix The prefix to use with the `FileStore`. Default value is `None` which means the database name is used. Selection --------- .. class:: Selection(selection, string[, sort[, selection_change_with[, translate[, \**options]]]) A string field with limited values to choice. :class:`Selection` has one extra required argument: .. attribute:: Selection.selection A list of 2-tuples that looks like this:: [ ('M', 'Male'), ('F', 'Female'), ] The first element in each tuple is the actual value stored. The second element is the human-readable name. It can also be the name of a class or instance method on the model, that will return an appropriate list. The signature of the method is:: selection() .. note:: The method is automaticly added to :attr:`trytond.model.Model._rpc` if not manually set. .. :class:`Selection` has two extra optional arguments: .. attribute:: Selection.sort If true, the choices will be sorted by human-readable value. Default value is ``True``. .. attribute:: Selection.selection_change_with A set of field names. If this attribute is set, the client will call the ``selection`` method of the model when the user changes on of the fields defined in the list and will give the values of each fields in the list. The ``selection`` method should be an instance method. The set of field names could be filled by using the decorator :meth:`depends`. .. attribute:: Selection.translate_selection If true, the human-readable values will be translated. Default value is ``True``. Instance methods: .. method:: Selection.translated([name]) Returns a descriptor for the translated value of the field. The descriptor must be used on the same class as the field. It will use the language defined in the context of the instance accessed. Reference --------- .. class:: Reference(string[, selection[, selection_change_with[, \**options]]) A field that refers to a record of a model. It will be represented in Python by a ``str`` instance like this:: ',' But a ``tuple`` can be used to search or set value. :class:`Reference` has three extra optional arguments: .. attribute:: Reference.selection Same as :attr:`Selection.selection` but only for model name. .. attribute:: Reference.selection_change_with Same as :attr:`Selection.selection_change_with`. .. attribute:: Reference.datetime_field Same as :attr:`Many2One.datetime_field` Many2One -------- .. class:: Many2One(model_name, string[, left[, right[, ondelete[, datetime_field[, target_search[, \**options]]]]]) A many-to-one relation field. :class:`Many2One` has one extra required argument: .. attribute:: Many2One.model_name The name of the target model. :class:`Many2One` has some extra optional arguments: .. attribute:: Many2One.left The name of the field that stores the left value for the `Modified Preorder Tree Traversal`_. It only works if the :attr:`model_name` is the same then the model. .. warning:: The MPTT Tree will be rebuild on database update if one record is found having left or right field value equals to the default or NULL. .. _`Modified Preorder Tree Traversal`: http://en.wikipedia.org/wiki/Tree_traversal .. attribute:: Many2One.right The name of the field that stores the right value. See :attr:`left`. .. attribute:: Many2One.ondelete Define the behavior of the record when the target record is deleted. Allowed values are: - ``CASCADE``: it will try to delete the record. - ``RESTRICT``: it will prevent the deletion of the target record. - ``SET NULL``: it will empty the relation field. ``SET NULL`` is the default setting. .. note:: ``SET NULL`` will be override into ``RESTRICT`` if :attr:`~Field.required` is true. .. .. attribute:: Many2One.datetime_field If set, the target record will be read at the date defined by the datetime field name of the record. It is usually used in combination with :attr:`trytond.model.ModelSQL._history` to request a value for a given date and time on a historicized model. .. attribute:: Many2One.target_search Define the kind of SQL query to use when searching on related target. Allowed values are: - ``subquery``: it will use a subquery based on the ids. - ``join``: it will add a join on the main query. ``join`` is the default value. .. note:: ``join`` could improve the performance if the target has a huge amount of records. .. One2Many -------- .. class:: One2Many(model_name, field, string[, add_remove[, order[, datetime_field[, size[, \**options]]]]]) A one-to-many relation field. It requires to have the opposite :class:`Many2One` field or a :class:`Reference` field defined on the target model. This field accepts as written value a list of tuples like this: - ``('create', [{: value, ...}, ...])``: it will create new target records and link them to this one. - ``('write'[[, ids, ...], {: value, ...}, ...])``: it will write values to target ids. - ``('delete'[, ids, ...])``: it will delete the target ids. - ``('add'[, ids, ...])``: it will link the target ids to this record. - ``('remove'[, ids, ...])``: it will unlink the target ids from this record. - ``('copy', ids[, {: value, ...}])``: it will copy the target ids to this record. Optional field names and values may be added to override some of the fields of the copied records. :class:`One2Many` has some extra required arguments: .. attribute:: One2Many.model_name The name of the target model. .. attribute:: One2Many.field The name of the field that handles the opposite :class:`Many2One` or :class:`Reference`. :class:`One2Many` has some extra optional arguments: .. attribute:: One2Many.add_remove A :ref:`domain ` to select records to add. If set, the client will allow to add/remove existing records instead of only create/delete. .. attribute:: One2Many.filter A :ref:`domain ` that is not a constraint but only a filter on the records. .. attribute:: One2Many.order A list of tuple defining the default order of the records like for :attr:`trytond.model.ModelSQL._order`. .. attribute:: One2Many.datetime_field Same as :attr:`Many2One.datetime_field` .. attribute:: One2Many.size An integer or a PYSON expression denoting the maximum number of records allowed in the relation. Many2Many --------- .. class:: Many2Many(relation_name, origin, target, string[, order[, datetime_field[, size[, \**options]]]]) A many-to-many relation field. It requires to have the opposite origin :class:`Many2One` field or a:class:`Reference` field defined on the relation model and a :class:`Many2One` field pointing to the target. This field accepts as written value a list of tuples like the :class:`One2Many`. :class:`Many2Many` has some extra required arguments: .. attribute:: Many2Many.relation_name The name of the relation model. .. attribute:: Many2Many.origin The name of the field that has the :class:`Many2One` or :class:`Reference` to the record. .. attribute:: Many2Many.target The name of the field that has the :class:`Many2One` to the target record. .. note:: A :class:`Many2Many` field can be used on a simple :class:`~trytond.model.ModelView`, like in a :class:`~trytond.wizard.Wizard`. For this, :attr:`~Many2Many.relation_name` is set to the target model and :attr:`~Many2Many.origin` and :attr:`~Many2Many.target` are set to `None`. .. :class:`Many2Many` has some extra optional arguments: .. attribute:: Many2Many.order Same as :attr:`One2Many.order` .. attribute:: Many2Many.datetime_field Same as :attr:`Many2One.datetime_field` .. attribute:: Many2Many.size An integer or a PYSON expression denoting the maximum number of records allowed in the relation. .. attribute:: Many2Many.add_remove An alias to the :attr:`domain` for compatibility with the :class:`One2Many`. .. attribute:: Many2Many.filter Same as :attr:`One2Many.filter` Instance methods: .. method:: Many2Many.get_target() Return the target :class:`~trytond.model.Model`. One2One ------- .. class:: One2One(relation_name, origin, target, string[, datetime_field[, \**options]]) A one-to-one relation field. .. warning:: It is on the relation_name :class:`~trytond.model.Model` that the unicity of the couple (origin, target) must be checked. .. .. attribute:: One2One.datetime_field Same as :attr:`Many2One.datetime_field` .. attribute:: One2MOne.filter Same as :attr:`One2Many.filter` Instance methods: .. method:: One2One.get_target() Return the target :class:`~trytond.model.Model`. Function -------- .. class:: Function(field, getter[, setter[, searcher]]) A function field can emulate any other given `field`. :class:`Function` has a required argument: .. attribute:: Function.getter The name of the classmethod or instance of the :class:`~trytond.model.Model` for getting values. The signature of the classmethod is:: getter(instances, name) where `name` is the name of the field, and it must return a dictionary with a value for each instance. Or the signature of the classmethod is:: getter(instances, names) where `names` is a list of name fields, and it must return a dictionary containing for each names a dictionary with a value for each instance. The signature of the instancemethod is:: getter(name) where `name` is the name of the field, and it must return the value. :class:`Function` has some extra optional arguments: .. attribute:: Function.setter The name of the classmethod of the :class:`~trytond.model.Model` to set the value. The signature of the method id:: setter(instances, name, value) where `name` is the name of the field and `value` the value to set. .. warning:: The modifications made to instances will not be saved automatically. .. attribute:: Function.searcher The name of the classmethod of the :class:`~trytond.model.Model` to search on the field. The signature of the method is:: searcher(name, clause) where `name` is the name of the field and `clause` is a :ref:`domain clause `. It must return a list of :ref:`domain ` clauses but the ``operand`` can be a SQL query. Instance methods: .. method:: Function.get(ids, model, name[, values]) Call the :attr:`~Function.getter` classmethod where `model` is the :class:`~trytond.model.Model` instance of the field, `name` is the name of the field. .. method:: Function.set(ids, model, name, value) Call the :attr:`~Function.setter` classmethod where `model` is the :class:`~trytond.model.Model` instance of the field, `name` is the name of the field, `value` is the value to set. .. method:: Function.search(model, name, clause) Call the :attr:`~Function.searcher` classmethod where `model` is the :class:`~trytond.model.Model` instance of the field, `name` is the name of the field, `clause` is a clause of :ref:`domain `. MultiValue ---------- .. class:: MultiValue(field) A multivalue field that is like a :class:`Function` field but with predefined :attr:`~Function.getter` and :attr:`~Function.setter` that use the :class:`~trytond.model.MultiValueMixin` for stored values. .. warning:: The :meth:`~trytond.model.MultiValueMixin.get_multivalue` and :meth:`~trytond.model.MultiValueMixin.set_multivalue` should be prefered over the descriptors of the field. .. .. warning:: The :ref:`default ` method of the field must accept pattern as keyword argument. .. Dict ---- .. class:: Dict(schema_model[, \**options]) A dictionary field with predefined keys. :class:`Dict` has one extra required argument: .. attribute:: Dict.schema_model The name of the :class:`DictSchemaMixin` model that stores the definition of keys. Instance methods: .. method:: Dict.translated([name[, type_]]) Returns a descriptor for the translated `values` or `keys` of the field following `type_`. The descriptor must be used on the same class as the field. Default `type_` is `values`.