DBSchema::DBD(3) User Contributed Perl Documentation DBSchema::DBD(3)NAMEDBIx::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.
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) 2007-2010 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.
BUGSSEE ALSO
DBIx::DBSchema, DBIx::DBSchema::DBD::mysql, DBIx::DBSchema::DBD::Pg,
DBIx::DBSchema::Index, DBI, DBI::DBD, perllol, "HASHES OF LISTS" in
perldsc
perl v5.18.2 2010-01-09 DBSchema::DBD(3)