references method

ColumnBuilder<T> references(Type table, Symbol column, { KeyAction? onUpdate, KeyAction? onDelete, bool initiallyDeferred = false, })

Adds a foreign-key reference from this column.

The table type must be a Dart class name defining a drift table. The column must be a Dart symbol with the same name as a column in the referenced table. In Dart, symbols can be created by prefixing an identifier with #.

In the following example, a Books table keeps a reference to the author of each book:

class Authors extends Table {
  IntColumn get id => integer().autoIncrement()();
  // ...
}

class Books extends Table {
  IntColumn get author => integer().references(Authors, #id)();
}

Important notice: In sqlite3, foreign keys are not enabled by default. When using foreign keys, remember to enable the option in the MigrationStrategy.beforeOpen callback:

beforeOpen: (details) async {
  await customStatement('PRAGMA foreign_keys = ON');
}

The optional onUpdate and onDelete actions can be used to automatically propagate changes from the referenced row to this column. See KeyAction for details.

initiallyDeferred can be set to true to generate the foreign key as DEFERRABLE INITIALLY DEFERRED, meaning that it is checked at the end of a transaction only instead of after every statement.

Implementation

ColumnBuilder<T> references(
  Type table,
  Symbol column, {
  KeyAction? onUpdate,
  KeyAction? onDelete,
  bool initiallyDeferred = false,
}) {
  _isGenerated();
}