Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like “Project has one Project Manager” or “Project belongs to a Portfolio”. Each macro adds a number of methods to the class which are specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby’s own attr methods.
Examples
- CheatSheet [pdf] from Slash7
- ForumExample: Demonstrates the use of
has_one,has_many, andbelongs_to. - AccessControlListExample: Demonstrates the use of
has_and_belongs_to_many*. - ActiveRecordAssociations (Pretty Picture)
Documentation
See also
Questions:
Q: Is there any way to create associations using multi-column primary keys in PostgreSQL?_
A: Rails only recognized one field for a primary key. Maybe you can use a pg View to work around this?
Thanks very much, that works quite well.
Associations are a set of macro-like class methods for tying objects together through foreign keys. They express relationships like “Project has one Project Manager” or “Project belongs to a Portfolio”. Each macro adds a number of methods to the class which are specialized according to the collection or association symbol and the options hash. It works much the same was as Ruby’s own attr methods.
Examples
- CheatSheet [pdf] from Slash7
- ForumExample: Demonstrates the use of
has_one,has_many, andbelongs_to. - AccessControlListExample: Demonstrates the use of
has_and_belongs_to_many*. - ActiveRecordAssociations (Pretty Picture)
Documentation
See also
Questions:
Q: Is there any way to create associations using multi-column primary keys in PostgreSQL?_
A: Rails only recognized one field for a primary key. Maybe you can use a pg View to work around this?
Thanks very much, that works quite well.