Schemas
=======

.. module:: pyrseas.dbobject.schema

The :mod:`schema` module defines two classes, :class:`Schema` and
:class:`SchemaDict`, derived from :class:`DbObject` and
:class:`DbObjectDict`, respectively.

Schema
------

:class:`Schema` is derived from :class:`~pyrseas.dbobject.DbObject`
and represents a database schema, i.e., a collection of tables and
other objects. The 'public' schema is special as in most contexts an
unqualified object is assumed to be part of it, e.g., table "t" is
usually shorthand for table "public.t."

For now, the schema :attr:`name` is the only attribute and is of
course the identifying attribute in the :class:`Schema`
:attr:`keylist`.

.. autoclass:: Schema

.. automethod:: Schema.to_map

.. automethod:: Schema.create

.. automethod:: Schema.diff_map

Schema Dictionary
-----------------

:class:`SchemaDict` is derived from
:class:`~pyrseas.dbobject.DbObjectDict`. It is a dictionary that
represents the collection of schemas in a database. Certain internal
schemas (information_schema, pg_catalog, etc.) owned by the 'postgres'
user are excluded.

.. autoclass:: SchemaDict

Method :meth:`from_map` is called from :class:`Database`
:meth:`~pyrseas.database.Database.from_map` to start a recursive
interpretation of the input map. The :obj:`inmap` argument is the same
as input to the :meth:`~pyrseas.database.Database.diff_map` method of
:class:`Database`. The :obj:`newdb` argument is the holder of
:class:`~pyrseas.dbobject.DbObjectDict`-derived dictionaries which is
filled in as the recursive interpretation proceeds.

.. automethod:: SchemaDict.from_map

.. automethod:: SchemaDict.link_refs

.. automethod:: SchemaDict.to_map

.. automethod:: SchemaDict.diff_map