CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4
MxLDevs
MxLDevs

Reputation: 19506

Adding default values to rails 4 migrations and updating existing records

Recently I realized that none of my database columns have default values. If an object is instantiated and then saved, it might have nil values for any fields that aren't filled out.

I can make it so that I explicitly initialize these values, but then I've got some places where two controllers are creating the same object, but I didn't think of moving that code into a separate module.

I can also choose to update my migrations to specify default values, which seems cleaner.

I've decided to go with migrations. It is not a good idea to edit old migrations, so I'm creating a new migration and specifying that I want to change certain columns.

Looking at how I should change columns, I have determined that I will use this

def change
  change_column :products, :size, :default => 0
end

Will this modify existing records that currently have nil set for those records?

Upvotes: 0

Views: 2400

Answers (1)

Anezio Campos
Anezio Campos

Reputation: 1555

No, it will not update your old records.

You should NEVER change old migrations, it is a relief you noticed that.

I suggest you to create a rake task that will update all the fields OR you can do it directly on console like the code below.

Product.update_all({ size: 0 }, { size: nil })

Upvotes: 2

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