gnu-social/lib/database/db/columndef.php

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<?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
* @param boolean $auto_increment
*/
function __construct($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));
}
}