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= 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
<code>:references</code> 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 <code>:references => nil</code>:
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
<code>:on_delete</code>/<code>:on_update</code>, respectively to one of:
<code>:cascade</code>; <code>:restrict</code>; and <code>:set_null</code>:
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:
* <code>config.active_record.pluralize_table_names</code>
* <code>config.active_record.table_name_prefix</code>
* <code>config.active_record.table_name_suffix</code>
=== Dependencies
* RedHill on Rails Core (redhillonrails_core).
=== See Also
* Foreign Key Associations (foreign_key_associations).
=== License
This plugin is copyright 2006 by RedHill Consulting, Pty. Ltd. and is released
under the MIT license.
Version data entries
80 entries across 80 versions & 1 rubygems