protected function parse_defaults( array $columns ) {
		foreach ( $columns as $column_name => $column ) {
			if ( array_key_exists( $column_name, $this->defaults ) ) {
				continue;
			}

			switch ( $column->get_mysql_type() ) {
				case 'TINYINT':
				case 'SMALLINT':
				case 'MEDIUMINT':
				case 'INT':
				case 'BIGINT':
					$this->defaults[ $column_name ] = 0;
					break;
				case 'FLOAT':
				case 'DOUBLE':
				case 'DECIMAL':
					$this->defaults[ $column_name ] = 0.0;
					break;
				case 'DATE':
				case 'DATETIME':
					$this->defaults[ $column_name ] = null;
					break;
				default:
					$this->defaults[ $column_name ] = '';
					break;
			}
		}
	}