Foreign Key Migrations
Foreign Key Migrations is a plugin that automatically generates foreign-key constraints when creating tables. It uses SQL-92 syntax and as such should be compatible with most databases that support foreign-key constraints.
In the simplest case, the plugin assumes that if you have a column named customer_id that you want a foreign-key constraint generated that references the id column in the customers table:
create_table :orders do |t| t.column :customer_id, :integer, :null => false ... end
If you have multiple columns referencing a table or for whatever reason, your column name isn’t the same as the referenced table name, you can use the :references option:
create_table :orders do |t| t.column :ordered_by_id, :integer, :null => false, :references => :customers ... end
If you have a column with a name ending in _id for which you do not wish a foreign-key to be generated, you can use :references => nil:
create_table :orders do |t| t.column :external_id, :integer, :null => false, :references => nil ... end
You also have the option of specifying what to do on delete/update using :on_delete/:on_update, respectively to one of: :cascade; :restrict; and :set_null:
create_table :orders do |t| t.column :customer_id, :integer, :on_delete => :set_null, :on_update => :cascade ... end
The plugin fully supports and understands the following active-record configuration properties:
- RedHill on Rails Core (redhillonrails_core).
- Foreign Key Associations (foreign_key_associations).
|Owner||Red Hill Consulting|
|Created||26 May 2006|