ActiveRecord::ConnectionAdapters::TableDefinition

Represents the schema of an SQL table in an abstract way. This class provides methods for manipulating the schema representation.

Inside migration files, the t object in create_table and change_table is actually of this type:

class SomeMigration < ActiveRecord::Migration
  def self.up
    create_table :foo do |t|
      puts t.class  # => "ActiveRecord::ConnectionAdapters::TableDefinition"
    end
  end

  def self.down
    ...
  end
end

The table definitions The Columns are stored as a ColumnDefinition in the columns attribute.