Question

I have a column named ‘parent_id’ that I am trying to add a default of -1 to:

change_column  :categories, :parent_id, :default => -1

The type is a integer in mysql.

I am getting the error:

'mysql2 error......'default-1 default null' at line 1:
alter table 'categories' change 'parent_id' 'parent_id' default-1 default null

It seems it is missing = sign?

Also, how do I do a db:migrate on the test db?

Answer 1

You’re missing the column type in your change_column, it should be more like this:

change_column :categories, :parent_id, :integer, :default => -1

The giveaway is this: default-1. The change_column method wants three arguments and then a hash of optional arguments. Your :default => -1 is getting mashed together as the column type because you didn’t specify :integer as the third argument.