change_column_default
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change_column_default(table_name, column_name, default_or_changes)
public
Sets a new default value for a column:
change_column_default(:suppliers, :qualification, 'new') change_column_default(:accounts, :authorized, 1)
Setting the default to nil effectively drops the default:
change_column_default(:users, :email, nil)
Passing a hash containing :from and :to will make this change reversible in migration:
change_column_default(:posts, :state, from: nil, to: "draft")
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Implemented in database adapters
These methods are not implemented in the abstract classes. Instead, all database adapters implement these separately, if the feature is supported.
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How to set default value to NULL
To set default value to NULL you can use change_column method instead, for example:
change_column :suppliers, :qualification, :string, :default => nil
Just make sure you don’t change data type accidentally ;-)
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Not implented yet
According to this method’s source, change_column_default is not implemented as well as change_column
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change_column did the trick for me
Use change_column, and make sure to specify the datatype:
class ChangeUsers < ActiveRecord::Migration def up change_column :users, :is_vote_reminder, :boolean, :default => true end end