CODEWITHSUNDEEP
ruby-on-railsormactiverecordnaming-conventions
blunders
blunders

Reputation: 3669

Does ActiveRecord assign a key to every table using the naming convention "ID", and if so, why?

My understanding is that Actice Record is based on a object-relational mapping (ORM) pattern described by Martin Fowler in his book Pattern of Enterprise Application Architecture (Addison-Wesley, 2002); which states a one-to-one mapping relationship exists between a database record and the object that represents it in an object-oriented program (OOP). When Rails creator David Heinemeier sought to implement an ORM for his Rails framework, he based it on Fowler's pattern.

Here's the problem, does ActiveRecord assign a surrogate primary key to every table using the naming convention "ID", and if so, why? Reason I ask is that it appears it'd make more sense to assign a a surrogate primary key using the naming convention "tablename_ID"; as in fact it appears ActiveRecord does when creating foreign keys. Further, is it possible to override the default config, and assign a surrogate primary key using the naming convention "tablename_ID"; reason being that especially in the case of primary keys, it appears to be a good idea not to use a shared name, since telling the difference between two columns ID's is not possible if simply looking at the column namesing: ID, ID, ID. As a use case example of where this appears there would be a problem, if I export data to a single table from two tables, there will be two columns with the ID name; when I import that document with updates, it would appear that there's no way to map the ID columns by default.

Upvotes: 1

Views: 466

Answers (1)

iain
iain

Reputation: 16274

It's already obvious to see what the ID is, because it is in a certain table. You don't have table_name.table_name_id but table_name.id. I like the distinction between foreign keys and primary keys this way, but admittedly, it's a matter of opinion.

Unless you have a really good reason to use anything other, you should stick to the convention. That's what conventions are for. ActiveRecord gives you the option to change it, like so:

ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore

This sets the way primary keys are generated globally. products.id becomes products.product_id.

Upvotes: 3

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