1 package DBIx::DBSchema::DBD;
10 DBIx::DBSchema::DBD - DBIx::DBSchema Driver Writer's Guide and Base Class
14 perldoc DBIx::DBSchema::DBD
16 package DBIx::DBSchema::DBD::FooBase
17 use DBIx::DBSchema::DBD;
18 @ISA = qw(DBIx::DBSchema::DBD);
22 Drivers should be named DBIx::DBSchema::DBD::DatabaseName, where DatabaseName
23 is the same as the DBD:: driver for this database. Drivers should implement the
24 following class methods:
28 =item columns CLASS DBI_DBH TABLE
30 Given an active DBI database handle, return a listref of listrefs (see
31 L<perllol>), each containing six elements: column name, column type,
32 nullability, column length, column default, and a field reserved for
35 =item column CLASS DBI_DBH TABLE COLUMN
37 Same as B<columns> above, except return the listref for a single column. You
38 can inherit from DBIx::DBSchema::DBD to provide this function.
43 my($proto, $dbh, $table, $column) = @_;
44 #@a = grep { $_->[0] eq $column } @{ $proto->columns( $dbh, $table ) };
47 grep { $_->[0] eq $column } @{ $proto->columns( $dbh, $table ) }
48 ] }[0]; #force list context on grep, return scalar of first element
51 =item primary_key CLASS DBI_DBH TABLE
53 Given an active DBI database handle, return the primary key for the specified
56 =item unique CLASS DBI_DBH TABLE
58 Deprecated method - see the B<indices> method for new drivers.
60 Given an active DBI database handle, return a hashref of unique indices. The
61 keys of the hashref are index names, and the values are arrayrefs which point
62 a list of column names for each. See L<perldsc/"HASHES OF LISTS"> and
63 L<DBIx::DBSchema::Index>.
65 =item index CLASS DBI_DBH TABLE
67 Deprecated method - see the B<indices> method for new drivers.
69 Given an active DBI database handle, return a hashref of (non-unique) indices.
70 The keys of the hashref are index names, and the values are arrayrefs which
71 point a list of column names for each. See L<perldsc/"HASHES OF LISTS"> and
72 L<DBIx::DBSchema::Index>.
74 =item indices CLASS DBI_DBH TABLE
76 Given an active DBI database handle, return a hashref of all indices, both
77 unique and non-unique. The keys of the hashref are index names, and the values
78 are again hashrefs with the following keys:
82 =item name - Index name (redundant)
84 =item using - Optional index method
86 =item unique - Boolean indicating whether or not this is a unique index
88 =item columns - List reference of column names (or expressions)
92 (See L<FS::DBIx::DBSchema::Index>)
94 New drivers are advised to implement this method, and existing drivers are
95 advised to (eventually) provide this method instead of B<index> and B<unique>.
97 For backwards-compatibility with current drivers, the base DBIx::DBSchema::DBD
98 class provides an B<indices> method which uses the old B<index> and B<unique>
99 methods to provide this data.
104 #my($proto, $dbh, $table) = @_;
105 my($proto, @param) = @_;
107 my $unique_hr = $proto->unique( @param );
108 my $index_hr = $proto->index( @param );
115 $_ => { 'name' => $_,
117 'columns' => $unique_hr->{$_},
125 $_ => { 'name' => $_,
127 'columns' => $index_hr->{$_},
137 =item default_db_catalog
139 Returns the default database catalog for the DBI table_info command.
140 Inheriting from DBIx::DBSchema::DBD will provide the default empty string.
144 sub default_db_catalog { ''; }
146 =item default_db_schema
148 Returns the default database schema for the DBI table_info command.
149 Inheriting from DBIx::DBSchema::DBD will provide the default empty string.
153 sub default_db_schema { ''; }
155 =item column_callback DBH TABLE_NAME COLUMN_OBJ
157 Optional callback for driver-specific overrides to SQL column definitions.
159 Should return a hash reference, empty for no action, or with one or more of
160 the following keys defined:
162 effective_type - Optional type override used during column creation.
164 explicit_null - Set true to have the column definition declare NULL columns explicitly
166 effective_default - Optional default override used during column creation.
168 effective_local - Optional local override used during column creation.
173 sub column_callback { {}; }
175 =item add_column_callback DBH TABLE_NAME COLUMN_OBJ
177 Optional callback for additional SQL statments to be called when adding columns
178 to an existing table.
180 Should return a hash reference, empty for no action, or with one or more of
181 the following keys defined:
183 effective_type - Optional type override used during column creation.
185 effective_null - Optional nullability override used during column creation.
187 sql_after - Array reference of SQL statements to be executed after the column is added.
191 sub add_column_callback { {}; }
193 =item alter_column_callback DBH TABLE_NAME OLD_COLUMN_OBJ NEW_COLUMN_OBJ
195 Optional callback for overriding the SQL statments to be called when altering
196 columns to an existing table.
198 Should return a hash reference, empty for no action, or with one or more of
199 the following keys defined:
201 sql_alter - Alter SQL statement(s) for changing everything about a column. Specifying this overrides processing of individual changes (type, nullability, default, etc.).
203 sql_alter_type - Alter SQL statement(s) for changing type and length (there is no default).
205 sql_alter_null - Alter SQL statement(s) for changing nullability to be used instead of the default.
209 sub alter_column_callback { {}; }
217 You can define a %typemap array for your driver to map "standard" data
218 types to database-specific types. For example, the MySQL TIMESTAMP field
219 has non-standard auto-updating semantics; the MySQL DATETIME type is
220 what other databases and the ODBC standard call TIMESTAMP, so one of the
221 entries in the MySQL %typemap is:
223 'TIMESTAMP' => 'DATETIME',
225 Another example is the Pg %typemap which maps the standard types BLOB and
226 LONG VARBINARY to the Pg-specific BYTEA:
229 'LONG VARBINARY' => 'BYTEA',
231 Make sure you use all uppercase-keys.
235 Ivan Kohler <ivan-dbix-dbschema@420.am>
239 Copyright (c) 2000-2005 Ivan Kohler
240 Copyright (c) 2007 Freeside Internet Services, Inc.
242 This program is free software; you can redistribute it and/or modify it under
243 the same terms as Perl itself.
249 L<DBIx::DBSchema>, L<DBIx::DBSchema::DBD::mysql>, L<DBIx::DBSchema::DBD::Pg>,
250 L<DBIx::DBSchema::Index>, L<DBI>, L<DBI::DBD>, L<perllol>,
251 L<perldsc/"HASHES OF LISTS">