Module: options
This module provides support for defining several options on your Elixir entities. There are three different kinds of options that can be set up, and for this there are three different statements: using_options, using_table_options and using_mapper_options.
Alternatively, these options can be set on all Elixir entities by modifying the options_defaults dictionary before defining any entity.
using_options
The 'using_options' DSL statement allows you to set up some additional behaviors on your model objects, including table names, ordering, and more. To specify an option, simply supply the option as a keyword argument onto the statement, as follows:
class Person(Entity): name = Field(Unicode(64)) using_options(shortnames=True, order_by='name')
The list of supported arguments are as follows:
| Option Name | Description |
|---|---|
| inheritance | Specify the type of inheritance this entity must use. It can be one of single or multi. Defaults to single. Concrete inheritance is currently not in a usable state. |
| polymorphic | Whether the inheritance should be polymorphic or not. Defaults to True. |
| metadata | Specify a custom MetaData for this entity. By default, entities uses the global elixir.metadata. This option can also be set for all entities of a module by setting the __metadata__ attribute of that module. |
| autoload | Automatically load column definitions from the existing database table. |
| tablename | Specify a custom tablename. You can either provide a plain string or a callable. The callable will be given the entity (ie class) as argument and must return a string representing the name of the table for that entity. |
| shortnames | Usually tablenames include the full module-path to the entity, but lower-cased and separated by underscores ("_"), eg.: "project1_model_myentity" for an entity named "MyEntity" in the module "project1.model". If shortnames is True, the tablename will just be the entity's classname lower-cased, ie. "myentity". |
| auto_primarykey | If given as string, it will represent the auto-primary-key's column name. If this option is True, it will allow auto-creation of a primary key if there's no primary key defined for the corresponding entity. If this option is False, it will disallow auto-creation of a primary key. |
| version_id_col | If this option is True, it will create a version column automatically using the default name. If given as string, it will create the column using that name. This can be used to prevent concurrent modifications to the entity's table rows (i.e. it will raise an exception if it happens). |
| order_by | How to order select results. Either a string or a list of strings, composed of the field name, optionally lead by a minus (for descending order). |
| session | Specify a custom contextual session for this entity. By default, entities uses the global elixir.session. This option accepts Objectstore (found in Elixir and ActiveMapper), SessionContext (found in SQLAlchemy 0.3) or ScopedSession (found in SQLAlchemy 0.4) objects. It also supports None, in which case your entity will be mapped using a non-contextual mapper. This option can also be set for all entities of a module via by setting the __session__ attribute of that module. |
| autosetup | Specify whether that entity will contain automatic setup triggers. That is if this entity will be automatically setup (along with all other entities which were already declared) if any of the following condition happen: some of its attributes are accessed ('c', 'table', 'mapper' or 'query'), instanciated (called) or the create_all method of this entity's metadata is called. Defaults to False. |
| allowcoloverride | Specify whether it is allowed to override columns. By default, Elixir forbids you to add a column to an entity's table which already exist in that table. If you set this option to True it will skip that check. Use with care as it is easy to shoot oneself in the foot when overriding columns. |
For examples, please refer to the examples and unit tests.
using_table_options
The 'using_table_options' DSL statement allows you to set up some additional options on your entity table. It is meant only to handle the options which are not supported directly by the 'using_options' statement. By opposition to the 'using_options' statement, these options are passed directly to the underlying SQLAlchemy Table object (both non-keyword arguments and keyword arguments) without any processing.
For further information, please refer to the SQLAlchemy table's documentation.
You might also be interested in the section about constraints.
using_mapper_options
The 'using_mapper_options' DSL statement allows you to set up some additional options on your entity mapper. It is meant only to handle the options which are not supported directly by the 'using_options' statement. By opposition to the 'using_options' statement, these options are passed directly to the underlying SQLAlchemy mapper (as keyword arguments) without any processing.
For further information, please refer to the SQLAlchemy mapper function's documentation.
Attributes
options_defaults
Value of options_defaults
None