1 package DBIx::DBSchema::DBD;
9 DBIx::DBSchema::DBD - DBIx::DBSchema Driver Writer's Guide and Base Class
13 perldoc DBIx::DBSchema::DBD
15 package DBIx::DBSchema::DBD::FooBase
16 use DBIx::DBSchema::DBD;
17 @ISA = qw(DBIx::DBSchema::DBD);
21 Drivers should be named DBIx::DBSchema::DBD::DatabaseName, where DatabaseName
22 is the same as the DBD:: driver for this database. Drivers should implement the
23 following class methods:
27 =item columns CLASS DBI_DBH TABLE
29 Given an active DBI database handle, return a listref of listrefs (see
30 L<perllol>), each containing six elements: column name, column type,
31 nullability, column length, column default, and a field reserved for
34 =item column CLASS DBI_DBH TABLE COLUMN
36 Same as B<columns> above, except return the listref for a single column. You
37 can inherit from DBIx::DBSchema::DBD to provide this function.
42 my($proto, $dbh, $table, $column) = @_;
43 #@a = grep { $_->[0] eq $column } @{ $proto->columns( $dbh, $table ) };
46 grep { $_->[0] eq $column } @{ $proto->columns( $dbh, $table ) }
47 ] }[0]; #force list context on grep, return scalar of first element
50 =item primary_key CLASS DBI_DBH TABLE
52 Given an active DBI database handle, return the primary key for the specified
55 =item unique CLASS DBI_DBH TABLE
57 Deprecated method - see the B<indices> method for new drivers.
59 Given an active DBI database handle, return a hashref of unique indices. The
60 keys of the hashref are index names, and the values are arrayrefs which point
61 a list of column names for each. See L<perldsc/"HASHES OF LISTS"> and
62 L<DBIx::DBSchema::Index>.
64 =item index CLASS DBI_DBH TABLE
66 Deprecated method - see the B<indices> method for new drivers.
68 Given an active DBI database handle, return a hashref of (non-unique) indices.
69 The keys of the hashref are index names, and the values are arrayrefs which
70 point a list of column names for each. See L<perldsc/"HASHES OF LISTS"> and
71 L<DBIx::DBSchema::Index>.
73 =item indices CLASS DBI_DBH TABLE
75 Given an active DBI database handle, return a hashref of all indices, both
76 unique and non-unique. The keys of the hashref are index names, and the values
77 are again hashrefs with the following keys:
81 =item name - Index name (redundant)
83 =item using - Optional index method
85 =item unique - Boolean indicating whether or not this is a unique index
87 =item columns - List reference of column names (or expressions)
91 (See L<FS::DBIx::DBSchema::Index>)
93 New drivers are advised to implement this method, and existing drivers are
94 advised to (eventually) provide this method instead of B<index> and B<unique>.
96 For backwards-compatibility with current drivers, the base DBIx::DBSchema::DBD
97 class provides an B<indices> method which uses the old B<index> and B<unique>
98 methods to provide this data.
103 #my($proto, $dbh, $table) = @_;
104 my($proto, @param) = @_;
106 my $unique_hr = $proto->unique( @param );
107 my $index_hr = $proto->index( @param );
114 $_ => { 'name' => $_,
116 'columns' => $unique_hr->{$_},
124 $_ => { 'name' => $_,
126 'columns' => $index_hr->{$_},
136 =item default_db_catalog
138 Returns the default database catalog for the DBI table_info command.
139 Inheriting from DBIx::DBSchema::DBD will provide the default empty string.
143 sub default_db_catalog { ''; }
145 =item default_db_schema
147 Returns the default database schema for the DBI table_info command.
148 Inheriting from DBIx::DBSchema::DBD will provide the default empty string.
152 sub default_db_schema { ''; }
154 =item constraints CLASS DBI_DBH TABLE
156 Given an active DBI database handle, return the constraints (currently, foreign
157 keys) for the specified table, as a list of hash references.
159 Each hash reference has the following keys:
163 =item constraint - contraint name
165 =item columns - List refrence of column names
167 =item table - Foreign taable name
169 =item references - List reference of column names in foreign table
181 sub constraints { (); }
183 =item column_callback DBH TABLE_NAME COLUMN_OBJ
185 Optional callback for driver-specific overrides to SQL column definitions.
187 Should return a hash reference, empty for no action, or with one or more of
188 the following keys defined:
190 effective_type - Optional type override used during column creation.
192 explicit_null - Set true to have the column definition declare NULL columns explicitly
194 effective_default - Optional default override used during column creation.
196 effective_local - Optional local override used during column creation.
201 sub column_callback { {}; }
203 =item add_column_callback DBH TABLE_NAME COLUMN_OBJ
205 Optional callback for additional SQL statments to be called when adding columns
206 to an existing table.
208 Should return a hash reference, empty for no action, or with one or more of
209 the following keys defined:
211 effective_type - Optional type override used during column creation.
213 effective_null - Optional nullability override used during column creation.
215 sql_after - Array reference of SQL statements to be executed after the column is added.
219 sub add_column_callback { {}; }
221 =item alter_column_callback DBH TABLE_NAME OLD_COLUMN_OBJ NEW_COLUMN_OBJ
223 Optional callback for overriding the SQL statments to be called when altering
224 columns to an existing table.
226 Should return a hash reference, empty for no action, or with one or more of
227 the following keys defined:
229 sql_alter - Alter SQL statement(s) for changing everything about a column. Specifying this overrides processing of individual changes (type, nullability, default, etc.).
231 sql_alter_type - Alter SQL statement(s) for changing type and length (there is no default).
233 sql_alter_null - Alter SQL statement(s) for changing nullability to be used instead of the default.
237 sub alter_column_callback { {}; }
239 =item column_value_needs_quoting COLUMN_OBJ
241 Optional callback for determining if a column's default value require quoting.
242 Returns true if it does, false otherwise.
246 sub column_value_needs_quoting {
247 my($proto, $col) = @_;
248 my $class = ref($proto) || $proto;
251 my %typemap = eval "\%${class}::typemap";
252 my $type = defined( $typemap{uc($col->type)} )
253 ? $typemap{uc($col->type)}
256 # false laziness: nicked from FS::Record::_quote
257 $col->default !~ /^\-?\d+(\.\d+)?$/
258 || $type =~ /(char|binary|blob|text)$/i;
266 You can define a %typemap array for your driver to map "standard" data
267 types to database-specific types. For example, the MySQL TIMESTAMP field
268 has non-standard auto-updating semantics; the MySQL DATETIME type is
269 what other databases and the ODBC standard call TIMESTAMP, so one of the
270 entries in the MySQL %typemap is:
272 'TIMESTAMP' => 'DATETIME',
274 Another example is the Pg %typemap which maps the standard types BLOB and
275 LONG VARBINARY to the Pg-specific BYTEA:
278 'LONG VARBINARY' => 'BYTEA',
280 Make sure you use all uppercase-keys.
284 Ivan Kohler <ivan-dbix-dbschema@420.am>
288 Copyright (c) 2000-2005 Ivan Kohler
289 Copyright (c) 2007-2013 Freeside Internet Services, Inc.
291 This program is free software; you can redistribute it and/or modify it under
292 the same terms as Perl itself.
298 L<DBIx::DBSchema>, L<DBIx::DBSchema::DBD::mysql>, L<DBIx::DBSchema::DBD::Pg>,
299 L<DBIx::DBSchema::Index>, L<DBI>, L<DBI::DBD>, L<perllol>,
300 L<perldsc/"HASHES OF LISTS">