ActiveRecord Validations for Models with has_many, belongs_to associations and STI

Posted by keruilin on Stack Overflow See other posts from Stack Overflow or by keruilin
Published on 2010-05-24T22:27:14Z Indexed on 2010/05/24 22:31 UTC
Read the original article Hit count: 229

Filed under:

ruby-on-rails

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validation

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activerecord

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single-table-inheritance

I have four models:

User
Award
Badge
GameWeek

The associations are as follows:

User has many awards.
Award belongs to user.
Badge has many awards.
Award belongs to badge.
User has many game_weeks.
GameWeek belongs to user.
GameWeek has many awards.
Award belongs to game_week.

Thus, user_id, badge_id and game_week_id are foreign keys in awards table.

Badge implements an STI model. Let's just say it has the following subclasses: BadgeA and BadgeB.

Some rules to note:

The game_week_id fk can be nil for BadgeA, but can't be nil for BadgeB.

Here are my questions:

For BadgeA, how do I write a validation that it can only be awarded one time? That is, the user can't have more than one -- ever.
For BadgeB, how do I write a validation that it can only be awarded one time per game week?

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