Database Objects ================ .. module:: pyrseas.dbobject The :mod:`dbobject` module defines two low-level classes and an intermediate class. Most Pyrseas classes are derived from either :class:`DbObject` or :class:`DbObjectDict`. Database Object --------------- A :class:`DbObject` represents a database object such as a schema, table, or column, defined in a PostgreSQL `system catalog `_. It is initialized from a dictionary of attributes. Derived classes should define a :attr:`keylist` that is a list of attribute names that uniquely identify each object instance within the database. .. autoclass:: DbObject .. autoattribute:: DbObject.objtype .. automethod:: DbObject.extern_key .. autoattribute:: DbObject.keylist .. automethod:: DbObject.key .. automethod:: DbObject.identifier .. automethod:: DbObject.to_map .. automethod:: DbObject.comment .. automethod:: DbObject.drop .. automethod:: DbObject.rename .. automethod:: DbObject.diff_description Database Object Dictionary -------------------------- A :class:`DbObjectDict` represents a collection of :class:`DbObject`'s and is derived from the Python built-in type :class:`dict`. If a :class:`~pyrseas.dbconn.DbConnection` object is used for initialization, an internal method is called to initialize the dictionary from the database catalogs. The :class:`DbObjectDict` :meth:`fetch` method fetches all objects using the :attr:`query` defined by derived classes. Derived classes should also define a :attr:`cls` attribute for the associated :class:`DbObject` class, e.g., :class:`~pyrseas.schema.SchemaDict` sets :attr:`cls` to :class:`~pyrseas.schema.Schema`. .. autoclass:: DbObjectDict .. autoattribute:: DbObjectDict.cls .. autoattribute:: DbObjectDict.query .. automethod:: DbObjectDict.fetch Schema Object ------------- A :class:`DbSchemaObject` is derived from :class:`DbObject`. It is used as a base class for objects owned by a schema and to define certain common methods. This is different from the :class:`~pyrseas.schema.Schema` that represents the schema itself. .. autoclass:: DbSchemaObject .. automethod:: DbSchemaObject.identifier .. automethod:: DbSchemaObject.qualname .. automethod:: DbSchemaObject.unqualify .. automethod:: DbSchemaObject.drop .. automethod:: DbSchemaObject.rename .. automethod:: DbSchemaObject.set_search_path