CODEWITHSUNDEEP
ruby-on-railsmodel-associations
user1447825
user1447825

Reputation:

Rails: Using migrations to create an association

I have a User table and a Product table. There is a has_many :products and a belongs_to :user relationship. I defined the Product and User models correctly...my question is about setting up the migration so that the schema comes out right. I tried and this was the extra line in the schema that i got.

add_index "product", ["user_id"], name: "index_product_on_user_id"

I then had a look online and instead of add_index other code had add_reference...does that matter? And not sure about the name: "index_product_on_user_id". Thanks!

Upvotes: 1

Views: 32

Answers (1)

Frederick Cheung
Frederick Cheung

Reputation: 84114

add_reference adds the required columns and (optionally) creates an index whereas add_index just creates the index, so if you want to use add_index you need to create the column separately.

You almost never need to set the index name - it doesn't affect how the index works or is used (one case is where the autogenerated index name exceeds the maximum index length).

Upvotes: 2

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