Plugins - Foreign Key Migrations - Agile Web Development

Plugins - 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:

config.active_record.pluralize_table_names
config.active_record.table_name_prefix
config.active_record.table_name_suffix

Dependencies

RedHill on Rails Core (redhillonrails_core).

Comments

Add a comment

Eric Pugh 1 Sep 2006

I also have FK's in the test environment. It was quite the project to figure out the issue, and I learned a lot! I tweaked init.rb to have a if statement: if ENV["RAILS_ENV"] != "test"

and also useing migrations for building the test db instead of using the rake clonestructureto_test call.

Simon Harris 24 Aug 2006

Hmm...it shouldn't be adding the foreign keys to your test database. any chance you could email me some sample code?

Eric Anderson 9 Aug 2006

I tried this plugin because I figure the more checks for valid data the better. The problem is when I tried to execute my unit testing it failed to load the fixtures since the records were inserted in an improper order. Any ideas on how to get around this.

Agile Web Development

Build it. Launch it. Love it.