class CommandRecorder

ActiveRecord::Migration::CommandRecorder records commands done during a migration and knows how to reverse those commands. The CommandRecorder knows how to invert the following commands:

• add_column

• add_foreign_key

• add_check_constraint

• add_index

• add_reference

• add_timestamps

• change_column

• change_column_default (must supply a :from and :to option)

• change_column_null

• change_column_comment (must supply a :from and :to option)

• change_table_comment (must supply a :from and :to option)

• create_join_table

• create_table

• disable_extension

• drop_join_table

• drop_table (must supply a block)

• enable_extension

• remove_column (must supply a type)

• remove_columns (must specify at least one column name or more)

• remove_foreign_key (must supply a second table)

• remove_check_constraint

• remove_index

• remove_reference

• remove_timestamps

• rename_column

• rename_index

• rename_table