abstract class CQL::Migration(V)

• CQL::Migration(V)
• CQL::BaseMigration
• Reference
• Object

Overview

Migrations are used to manage changes to the database schema over time. Each migration is a subclass of Migration(V), where V is its version, and implements up and down.

The up method applies the migration, while the down method rolls it back. Migrations run in version order. Defining the class registers it with Migrator, which applies, rolls back and redoes migrations and lists the applied and pending ones.

Example Creating a new migration

class AddPhoneToUsers < CQL::Migration(1)
  def up
    schema.alter :users do
      add_column :phone, String, null: true
    end
  end

  def down
    schema.alter :users do
      drop_column :phone
    end
  end
end

Example Applying and rolling back migrations

migrator = CQL::Migrator.new(schema)
migrator.up
migrator.rollback

Defined in:

Constructors

• .new(schema : CQL::Schema)

  Migrator calls .new(schema) on every registered class, which must resolve even when no migration class exists.

Constructor Detail