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

NAME SYNOPSIS DESCRIPTION TYPE MAPPING AUTHOR COPYRIGHT BUGS SEE ALSO

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);

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.