Unconstrained

Unconstrained for Active Record converts exceptions raised because of underlying foreign key constraints to appropriate ActiveModel::Errors

For example, if trying to insert a record in a model Book, which belongs_to :author using an invalid author_id, instead of getting an exception such as:

PG::ForeignKeyViolation: ERROR:  insert or update on table "books" 
violates foreign key constraint "fk_rails_xxxxxxxxxx"
DETAIL:  Key (author_id)=(xxxxxxxxxx) is not present in table "authors".

you will now get a validation error on the field author_id with the message "author is invalid"

Conversely, when if trying to delete an author but books exist, instead of:

PG::ForeignKeyViolation: ERROR:  update or delete on table "authors" 
violates foreign key constraint "fk_rails_xxxxxxxxxx" on table "books"
DETAIL:  Key (id)=(xxxxxxxxxx) is still referenced from table "books".

you will now get a base validation error on the record with the message "Cannot delete record because dependent books exist"

Usage

In your Gemfile:

gem 'unconstrained'

Notes

Only constraints that have to do with referential integrity are handled. This is intentional, as these require a roundrip to the database anyway. Constraints that can be enforced using validations in the application should be checked that way.

Currently only handles PostgreSQL.