FkConstraints
=============

Here's a plugin to add foreign keys for associations. Postgres only for now. It
doesn't have any dependencies. And it's code is simple so it can be read in one
take. The Two things that I like in plugins.

In migrations, when a table is created, it recognizes columns which are foreign
keys by _id suffix. Then it adds foreign key constraint declarations. Referred
table name is guessed from column's name according to rails conventions.

If a column should refer to a table which name can't be inferred that way,
you can explicitly specify it by using a symbol or a string. They offer
different type of control. Symbols are nice to name tables so:

 create_table :comments do |t|
   t.integer :post_id, :references => :posts
 end

will produce

 CREATE TABLE comments(
 ...
 post_id INTEGER REFERENCES posts
 ...
 );


And with strings you can do all the things that you shouldn't want to do:

 ... :references => 'whatever(strange_pk) ON DELETE RESTRICT'

 ... REFERENCES whatever(strange_pk) ON DELETE RESTRICT

That can become handy when dealing with nasty legacy schemas.

And you can add foreign key constraints for already created tables:


 add_fk_constraint(:posts, :comment_id, :comments, :p_id)

will execute

 ALTER TABLE posts ADD FOREIGN KEY (comment_id) REFERENCES comments(p_id);


 More examples
 -------------

 Please find more examples in spec/migration_spec.rb


 Fixtures
 --------

Recent versions of Rails disable referrential integrity before loading
fixtures, so your foreign key constraints shouldn't make much trouble in tests.


 Install
 -------

To install run this command from your app root directory:

 ./script/plugin install git://github.com/bgipsy/fk_constraints.git




Tested with postgres 8.2 & Rails 2.3.2

Copyright (c) 2009 [Serg Balyuk], released under the MIT license