一个PHP动态数据库基础类

renran421

参考:http://www.ibm.com/developerworks/cn/opensource/os-php-flexobj/
需要PHP5支持才行,使用了__call __get __set等动态方法

class DBObject
{
private $id = 0;
private $table;
private $fields = array();
function __construct( $table, $fields )
{
$this->table = $table; //数据表名
foreach( $fields as $key )
$this->fields[ $key ] = null; //数据字段
}
function __get( $key )   //可读字段
{
return $this->fields[ $key ];
}
function __set( $key, $value ) //可写字段
{
if ( array_key_exists( $key, $this->fields ) )
{                                //添加条件可以限制某些字段不能写
$this->fields[ $key ] = $value;
return true;
}
return false;
}
function load( $id )
{
global $db;  //数据库对象
$res = $db->query(
"SELECT * FROM ".$this->table." WHERE ".
$this->table."_id=?",
array( $id )
);
$res->fetchInto( $row, DB_FETCHMODE_ASSOC );
$this->id = $id;
foreach( array_keys( $row ) as $key )
$this->fields[ $key ] = $row[ $key ];
}
function insert()
{
global $db;
$fields = $this->table."_id, ";
$fields .= join( ", ", array_keys( $this->fields ) );
$inspoints = array( "0" );
foreach( array_keys( $this->fields ) as $field )
$inspoints []= "?";
$inspt = join( ", ", $inspoints );
$sql = "INSERT INTO ".$this->table." ( $fields )
VALUES ( $inspt )";
$values = array();
foreach( array_keys( $this->fields ) as $field )
$values []= $this->fields[ $field ];
$sth = $db->prepare( $sql );
$db->execute( $sth, $values );
$res = $db->query( "SELECT last_insert_id()" );
$res->fetchInto( $row );
$this->id = $row[0];
return $row[0];
}
function update()
{
global $db;
$sets = array();
$values = array();
foreach( array_keys( $this->fields ) as $field )
{
$sets []= $field.'=?';
$values []= $this->fields[ $field ];
}
$set = join( ", ", $sets );
$values []= $this->id;
$sql = 'UPDATE '.$this->table.' SET '.$set.
' WHERE '.$this->table.'_id=?';
$sth = $db->prepare( $sql );
$db->execute( $sth, $values );
}
function delete()
{
global $db;
$sth = $db->prepare(
'DELETE FROM '.$this->table.' WHERE '.
$this->table.'_id=?'
);
$db->execute( $sth,
array( $this->id ) );
}
function delete_all()
{
global $db;
$sth = $db->prepare( 'DELETE FROM '.$this->table );
$db->execute( $sth );
}
}

继承时覆盖_construct 方法

function __construct()
{
parent::__construct( 'book',
array( 'author', 'title', 'publisher' ) );
}