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Diffstat (limited to 'lib/columndef.php')
| -rw-r--r-- | lib/columndef.php | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/lib/columndef.php b/lib/columndef.php new file mode 100644 index 000000000..1bae6b33b --- /dev/null +++ b/lib/columndef.php @@ -0,0 +1,169 @@ +<?php +/** + * StatusNet, the distributed open-source microblogging tool + * + * Database schema utilities + * + * PHP version 5 + * + * LICENCE: This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * @category Database + * @package StatusNet + * @author Evan Prodromou <evan@status.net> + * @copyright 2009 StatusNet, Inc. + * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 + * @link http://status.net/ + */ + +if (!defined('STATUSNET')) { + exit(1); +} + +/** + * A class encapsulating the structure of a column in a table. + * + * @category Database + * @package StatusNet + * @author Evan Prodromou <evan@status.net> + * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 + * @link http://status.net/ + */ + +class ColumnDef +{ + /** name of the column. */ + public $name; + /** type of column, e.g. 'int', 'varchar' */ + public $type; + /** size of the column. */ + public $size; + /** boolean flag; can it be null? */ + public $nullable; + /** + * type of key: null = no key; 'PRI' => primary; + * 'UNI' => unique key; 'MUL' => multiple values. + */ + public $key; + /** default value if any. */ + public $default; + /** 'extra' stuff. Returned by MySQL, largely + * unused. */ + public $extra; + /** auto increment this field if no value is specific for it during an insert **/ + public $auto_increment; + + /** + * Constructor. + * + * @param string $name name of the column + * @param string $type type of the column + * @param int $size size of the column + * @param boolean $nullable can this be null? + * @param string $key type of key + * @param value $default default value + * @param value $extra unused + */ + + function __construct($name=null, $type=null, $size=null, + $nullable=true, $key=null, $default=null, + $extra=null, $auto_increment=false) + { + $this->name = strtolower($name); + $this->type = strtolower($type); + $this->size = $size+0; + $this->nullable = $nullable; + $this->key = $key; + $this->default = $default; + $this->extra = $extra; + $this->auto_increment = $auto_increment; + } + + /** + * Compares this columndef with another to see + * if they're functionally equivalent. + * + * @param ColumnDef $other column to compare + * + * @return boolean true if equivalent, otherwise false. + */ + + function equals($other) + { + return ($this->name == $other->name && + $this->_typeMatch($other) && + $this->_defaultMatch($other) && + $this->_nullMatch($other) && + $this->key == $other->key && + $this->auto_increment == $other->auto_increment); + } + + /** + * Does the type of this column match the + * type of the other column? + * + * Checks the type and size of a column. Tries + * to ignore differences between synonymous + * data types, like 'integer' and 'int'. + * + * @param ColumnDef $other other column to check + * + * @return boolean true if they're about equivalent + */ + + private function _typeMatch($other) + { + switch ($this->type) { + case 'integer': + case 'int': + return ($other->type == 'integer' || + $other->type == 'int'); + break; + default: + return ($this->type == $other->type && + $this->size == $other->size); + } + } + + /** + * Does the default behaviour of this column match + * the other? + * + * @param ColumnDef $other other column to check + * + * @return boolean true if defaults are effectively the same. + */ + + private function _defaultMatch($other) + { + return ((is_null($this->default) && is_null($other->default)) || + ($this->default == $other->default)); + } + + /** + * Does the null behaviour of this column match + * the other? + * + * @param ColumnDef $other other column to check + * + * @return boolean true if these columns 'null' the same. + */ + + private function _nullMatch($other) + { + return ((!is_null($this->default) && !is_null($other->default) && + $this->default == $other->default) || + ($this->nullable == $other->nullable)); + } +} |