+
+ def change_column(table_name, column_name, type, options = {})
+ unless options_include_default?(options)
+ options[:default] = select_one("SHOW COLUMNS FROM #{table_name} LIKE '#{column_name}'")["Default"]
+
+ unless type == :string or type == :text
+ options.delete(:default) if options[:default] = "";
+ end
+ end
+
+ change_column_sql = "ALTER TABLE #{table_name} CHANGE #{column_name} #{column_name} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
+ add_column_options!(change_column_sql, options)
+ execute(change_column_sql)
+ end
+
+ def myisam_table
+ return { :id => false, :force => true, :options => "ENGINE=MyIsam" }
+ end
+
+ def innodb_table
+ return { :id => false, :force => true, :options => "ENGINE=InnoDB" }
+ end