NAME

       DBIx::DBSchema::DBD - DBIx::DBSchema Driver Writer's Guide and Base Class

SYNOPSIS

         perldoc DBIx::DBSchema::DBD

         package DBIx::DBSchema::DBD::FooBase
         use DBIx::DBSchema::DBD;
         @ISA = qw(DBIx::DBSchema::DBD);

DESCRIPTION

       Drivers should be named DBIx::DBSchema::DBD::DatabaseName, where DatabaseName is the same
       as the DBD:: driver for this database.  Drivers should implement the following class
       methods:

       columns CLASS DBI_DBH TABLE
           Given an active DBI database handle, return a listref of listrefs (see perllol), each
           containing six elements: column name, column type, nullability, column length, column
           default, and a field reserved for driver-specific use.

       column CLASS DBI_DBH TABLE COLUMN
           Same as columns above, except return the listref for a single column.  You can inherit
           from DBIx::DBSchema::DBD to provide this function.

       primary_key CLASS DBI_DBH TABLE
           Given an active DBI database handle, return the primary key for the specified table.

       unique CLASS DBI_DBH TABLE
           Deprecated method - see the indices method for new drivers.

           Given an active DBI database handle, return a hashref of unique indices.  The keys of
           the hashref are index names, and the values are arrayrefs which point a list of column
           names for each.  See "HASHES OF LISTS" in perldsc and DBIx::DBSchema::Index.

       index CLASS DBI_DBH TABLE
           Deprecated method - see the indices method for new drivers.

           Given an active DBI database handle, return a hashref of (non-unique) indices.  The
           keys of the hashref are index names, and the values are arrayrefs which point a list
           of column names for each.  See "HASHES OF LISTS" in perldsc and DBIx::DBSchema::Index.

       indices CLASS DBI_DBH TABLE
           Given an active DBI database handle, return a hashref of all indices, both unique and
           non-unique.  The keys of the hashref are index names, and the values are again
           hashrefs with the following keys:

           name - Index name (redundant)
           using - Optional index method
           unique - Boolean indicating whether or not this is a unique index
           columns - List reference of column names (or expressions)

           (See FS::DBIx::DBSchema::Index)

           New drivers are advised to implement this method, and existing drivers are advised to
           (eventually) provide this method instead of index and unique.

           For backwards-compatibility with current drivers, the base DBIx::DBSchema::DBD class
           provides an indices method which uses the old index and unique methods to provide this
           data.

       default_db_catalog
           Returns the default database catalog for the DBI table_info command.  Inheriting from
           DBIx::DBSchema::DBD will provide the default empty string.

       default_db_schema
           Returns the default database schema for the DBI table_info command.  Inheriting from
           DBIx::DBSchema::DBD will provide the default empty string.

       constraints CLASS DBI_DBH TABLE
           Given an active DBI database handle, return the constraints (currently, foreign keys)
           for the specified table, as a list of hash references.

           Each hash reference has the following keys:

           constraint - contraint name
           columns - List refrence of column names
           table - Foreign taable name
           references - List reference of column names in foreign table
           match -
           on_delete -
           on_update -
       column_callback DBH TABLE_NAME COLUMN_OBJ
           Optional callback for driver-specific overrides to SQL column definitions.

           Should return a hash reference, empty for no action, or with one or more of the
           following keys defined:

           effective_type - Optional type override used during column creation.

           explicit_null - Set true to have the column definition declare NULL columns explicitly

           effective_default - Optional default override used during column creation.

           effective_local - Optional local override used during column creation.

       add_column_callback DBH TABLE_NAME COLUMN_OBJ
           Optional callback for additional SQL statments to be called when adding columns to an
           existing table.

           Should return a hash reference, empty for no action, or with one or more of the
           following keys defined:

           effective_type - Optional type override used during column creation.

           effective_null - Optional nullability override used during column creation.

           sql_after - Array reference of SQL statements to be executed after the column is
           added.

       alter_column_callback DBH TABLE_NAME OLD_COLUMN_OBJ NEW_COLUMN_OBJ
           Optional callback for overriding the SQL statments to be called when altering columns
           to an existing table.

           Should return a hash reference, empty for no action, or with one or more of the
           following keys defined:

           sql_alter - Alter SQL statement(s) for changing everything about a column.  Specifying
           this overrides processing of individual changes (type, nullability, default, etc.).

           sql_alter_type - Alter SQL statement(s) for changing type and length (there is no
           default).

           sql_alter_null - Alter SQL statement(s) for changing nullability to be used instead of
           the default.

       column_value_needs_quoting COLUMN_OBJ
           Optional callback for determining if a column's default value require quoting.
           Returns true if it does, false otherwise.

TYPE MAPPING

       You can define a %typemap array for your driver to map "standard" data types to database-
       specific types.  For example, the MySQL TIMESTAMP field has non-standard auto-updating
       semantics; the MySQL DATETIME type is what other databases and the ODBC standard call
       TIMESTAMP, so one of the entries in the MySQL %typemap is:

         'TIMESTAMP' => 'DATETIME',

       Another example is the Pg %typemap which maps the standard types BLOB and LONG VARBINARY
       to the Pg-specific BYTEA:

         'BLOB' => 'BYTEA',
         'LONG VARBINARY' => 'BYTEA',

       Make sure you use all uppercase-keys.

AUTHOR

       Ivan Kohler <ivan-dbix-dbschema@420.am>

COPYRIGHT

       Copyright (c) 2000-2005 Ivan Kohler Copyright (c) 2007-2013 Freeside Internet Services,
       Inc.  All rights reserved.  This program is free software; you can redistribute it and/or
       modify it under the same terms as Perl itself.

BUGS

SEE ALSO

       DBIx::DBSchema, DBIx::DBSchema::DBD::mysql, DBIx::DBSchema::DBD::Pg,
       DBIx::DBSchema::Index, DBI, DBI::DBD, perllol, "HASHES OF LISTS" in perldsc