PEAR DB_DataObject 简介

进阶

配置选项

共有三个ini文件存放各种信息，

DataObject.ini （或config.ini）名字由用户自己定义。设置数据库、路径等信息
db.ini 执行CreateDataObjectClasses.php自动创建，保存数据库各字段的类型
db.links.ini 保存表间关系，不同表通过什么字段来联系。

其中db用你的数据库名称替换。

DataObject.ini
信息放在[DB_DataObject]段内

CREATE TABLE IF NOT EXISTS `hr_employee` (
`id` smallint(5) unsigned NOT NULL auto_increment,
`name` varchar(20) NOT NULL default '',
`section_id` tinyint(3) unsigned NOT NULL default '0',
PRIMARY KEY (`id`),
) TYPE=MyISAM COMMENT='员工表';
CREATE TABLE IF NOT EXISTS `hr_section` (
`id` tinyint(3) unsigned NOT NULL auto_increment,
`name` varchar(20) NOT NULL default '',
PRIMARY KEY (`id`),
UNIQUE KEY `name` (`name`)
) TYPE=MyISAM COMMENT='部门表' ;
 
CREATE TABLE IF NOT EXISTS `hr_project` (
`id` smallint(5) unsigned NOT NULL auto_increment,
`name` varchar(60) NOT NULL default '',
`date` date NOT NULL default '0000-00-00',
PRIMARY KEY (`id`),
UNIQUE KEY `name` (`name`)
) TYPE=MyISAM COMMENT='项目表' ;
 
CREATE TABLE IF NOT EXISTS `hr_employee_project` (
`id` int(11) unsigned NOT NULL auto_increment,
`employee_id` smallint(5) unsigned NOT NULL default '0',
`project_id` smallint(5) unsigned NOT NULL default '0',
PRIMARY KEY (`id`),
UNIQUE KEY `employee_id` (`employee_id`,`project_id`)
) TYPE=MyISAM COMMENT='员工-项目表';

database：数据库访问信息，与DB的格式一样

schema_location：存放表间关系的ini文件

class_location：自动生成的DataObject类放置的路径

require_prefix：派生类放置的路径，最后为“/”。与include路径的相对路径。 staticGet()和getLinks()方法自动载入类时要搜索到相应的类。

一个linux下的例子：
example.ini:

 [DB_DataObject]
 database = mysql://user:password@server/database 
 schema_location = /DataObjects
 class_location  = /DataObjects
 require_prefix  = /DataObjects/

<?php
   //注意设置好你的pear包含路径
   require_once 'd:/www/Pear/DB/DataObject/Generator.php';
   $config = parse_ini_file("D:\www\hr\DataObjects\DataObject.ini", true);
       $options = &PEAR::getStaticProperty('DB_DataObject','options');
   $options = $config['DB_DataObject'];
       if (!$options) {
       PEAR::raiseError("\n错误:无法读取ini文件\n\n", null, PEAR_ERROR_DIE);
       exit;   
       }
   set_time_limit(0);
   DB_DataObject::debugLevel(1);
   $generator = new DB_DataObject_Generator;
   $generator->start();
 ?>

上述四个是必先项,以下为可选项：

sequence_{table} string：强行设置次序键（autoincrement/nextval类型)。当主键不能被正确识别而运行不正确，可以强行设置次序键

例如：sequence_person = login 将person表的次序键设为login字段。

ignore_sequence_keys string 忽略顺序键

If you do not want to use pear’s nextval(), for automatically filling in sequences, this can disable it for “ALL”, or a list of tables “person,cart,group”

debug integer 调试级别。这个选项非常有用，调试时可以看到运行的情况。不过我一般会用->debug() 方法在一个公共文件中设置。默认为关闭 (default 0=off), 1= basic sql logging,2=result logging, 3=everything

debug_ignore_updates boolean default FALSE, if set, then updates on the database are disabled.

dont_die boolean default FALSE, The standard behaviour of dataobjects is to issue a PEAR_ERROR_DIE (eg. exiting PHP), when a fatal error occurs, like database connection failure or sending an invalid object type to a method. However if you need to run it on a live server you will probably want to set this to TRUE and define a PEAR error handler to catch these errors and show a nice friendly ‘sorry we are down for maintenence’ message page.

Configuration Options – Multiple Databases (optional)

database_* string When you have multiple databases you can use the database_* to specify the DSN for each database

Example 20-4. using multiple databases – database passwords

 [hr_employee] section_id = hr_section:id 
[hr_employee_project] employee_id = hr_employee:id 
project_id = hr_training_project:id 
[hr_project] id = hr_employee:id

table_* string When you have multiple databases you can use the table_* configuration variables to map individual tables to different databases, for example

Example 20-5. using multiple databases – table settings

 <? 
//取单个表的数据
 $employee = new Hr_employee;
 $employee->name = '张三';
 $employee->find(ture);
 echo '员工'.$employee->name.'的职务是'.$employee->position.', ';
    //取多对一关系的数据
  $employee->getLinks();
   echo '工作部门是'.$employee->_section_id->name.'，';
   //取多对多关系的数据 echo '参加的项目包括';
 $e_p = new Hr_employee_project;
 $e_p->employee_id = $employee->id;
 $e_p->find();
 while ($e_p->fetch()) {   $project = $e_p->getLink('project_id');
    echo $project->name.'、';
 }
 echo '。'; 
?>

Configuration Options – Builder

class_location directory The Directory where your DataObject extended Classes are.

Used by the Class Auto Builder when updating/writing to your class definitions.

extends string The Name of your Base Class (usually DB_DataObject) is located.

If you wish to add a common layer of useful methods for all classes, you can set the extends_location and extends settings to a different class. the default is ‘DB_DataObject’

extends_location directory The Directory where your Base Class (usually DB_DataObject) is located.

If you wish to add a common layer of useful methods for all classes, you can set the extends_location and extends settings to a different class. the default is ‘DB/DataObject.php’

generator_class_rewrite directory

定义表间关系 db.links.ini

结构

表间关系
1:1（一对一关系）

n:1（一对多关系，或者是多对一关系）通常表示一个对象的属性也是一个对象。

n:m（多对多关系）使用一个十字链表（crossLink table）表示它们之间的关系。

对数据表的要求

每个表的主键(primaryKey)必须是一个以唯一数字标识的字段(sequenceKey)，在mysql中就是auto_increment的字段。不可以使用非整型的字段作为主键，即使是设为unique；也不可以用多字段做主键。这与数据库设计的理论有些不同。例如以username作为主键，会出现找不到键的错误。虽然可以用 keys()方法强行设置主键，但我建议不要这样做。