1.20.x system.api.php | hook_schema_alter(&$schema) |
Perform alterations to existing database schemas.
When a module modifies the database structure of another module (by changing, adding or removing fields, keys or indexes), it should implement hook_schema_alter() to update the default $schema to take its changes into account.
See hook_schema() for details on the schema definition structure.
Parameters
$schema: Nested array describing the schemas for all modules.
Related topics
File
- modules/
system/ system.api.php, line 2643 - Hooks provided by Backdrop core and the System module.
Code
function hook_schema_alter(&$schema) {
// Add field to existing schema.
$schema['users']['fields']['timezone_id'] = array(
'type' => 'int',
'not null' => TRUE,
'default' => 0,
'description' => 'Per-user timezone configuration.',
);
}