zend framework 如何多表查询

Zend_Db_Select

简介

使用Zend_Db_Select方法是一种不受数据库约束构建select的sql语句的工具 （ares注：用户可以使用该方法生成查询的sql语句，而不需要考虑各种数据 库sql语句的差别）。虽然该方法明显还不完善，但是的确为我们提供一种方 法，帮助我们在不同的后台数据库进行相同的查询工作。除此之外，它还可 以避免sql语句攻击。

创建一个zend_db_select实例最简单的方法就是使用zend_db_adapter::select()方法

<?phprequire_once 'Zend/Db.php';$params = array (    'host'     => '127.0.0.1',    'username' => 'malory',    'password' => '******',    'dbname'   => 'camelot');$db = Zend_Db::factory('PDO_MYSQL', $params);$select = $db->select();// $select现在是一个Zend_Db_Select_PdoMysql对象?>

你可以使用该对象和它的相应方法构建一个select查询语句，然后生成 字符串符用来传送给zend_db_adapter进行查询或者读取结果。

<?php//// SELECT *//     FROM round_table//     WHERE noble_title = "Sir"//     ORDER BY first_name//     LIMIT 10 OFFSET 20//// 你可以使用一种重复定义的方式...$select->from('round_table', '*');$select->where('noble_title = ?', 'Sir');$select->order('first_name');$select->limit(10,20);// ...或者使用一种连续定义的方式:$select->from('round_table', '*')       ->where('noble_title = ?', 'Sir')       ->order('first_name')       ->limit(10,20);// 但是，读取数据的方法相同$sql = $select->__toString();$result = $db->fetchAll($sql);// 对于以上任一种方式，你都可以传送$select对象本身// 使用Zend_Db_Select对象的 __toString()方法就可以得到查询语句$result = $db->fetchAll($select);?>

你也可以在你的查询语句中使用绑定的参数，而不需要自己为参数加引号。

<?php//// SELECT *//     FROM round_table//     WHERE noble_title = "Sir"//     ORDER BY first_name//     LIMIT 10 OFFSET 20//$select->from('round_table', '*')       ->where('noble_title = :title')       ->order('first_name')       ->limit(10,20);// 读取结果使用绑定的参数$params = array('title' => 'Sir');$result = $db->fetchAll($select, $params);?>

同一表中查询多列数据

当需要从某一个指定的表查询某几列时，可以使用from()方法，将需要 查询的表名和列名都在该方法中指定。表名和列名都可以通过别名代替 ，而且也可以根据需要多次使用from()方法。

<?php// 创建一个$db对象，假定adapter为Mysql$select = $db->select();// 从some_table表中读取a,b,c三列$select->from('some_table', 'a, b, c');// 同样可以:$select->from('some_table', array('a', 'b', 'c');// 从foo AS bar表中读取列bar.col$select->from('foo AS bar', 'bar.col');// 从foo, bar两个表中读取foo.col 别名为col1，bar.col别名为col2$select->from('foo', 'foo.col AS col1');$select->from('bar', 'bar.col AS col2');?>

多表联合查询

当需要进行表联合查询时，可以使用join()方法。首先，设定进行表 联合查询的表名，然后是表联合的条件(ares注：该条件是针对多表 内部连接的条件)，最后是查询的列名。同样，你可以根据需要多次 使用join()方法。

<?php// 创建一个$db对象，假定adapter为Mysql.$select = $db->select();//// SELECT foo.*, bar.*//     FROM foo//     JOIN bar ON foo.id = bar.id//$select->from('foo', '*');$select->join('bar', 'foo.id = bar.id', '*');?>

目前为止，zend framework只支持普通的内部表结合语法，而不支持左结合 ，右结合，等等外部连接方式。未来版本，将会更多的支持更多的连接方式。

WHERE条件

当需要要增加where条件时，可以使用where（）方法。你可以传送一个 普通的查询语句字符串，也可以传送一个使用？作为占位符的字符串,然 后在占位符处加入通过加引号处理后的数据(将使用Zend_Db_Adapter::quoteInto方法进行数据处理)

Multiple calls to where() will AND the conditions together; if you need to OR a condition, use orWhere().

<?php// 创建一个$db对象，调用SELECT方法.$select = $db->select();//// SELECT *//     FROM round_table//     WHERE noble_title = "Sir"//     AND favorite_color = "yellow"//$select->from('round_table', '*');$select->where('noble_title = "Sir"'); // embedded value$select->where('favorite_color = ?', 'yellow'); // quoted value//// SELECT *//     FROM foo//     WHERE bar = "baz"//     OR id IN("1", "2", "3")//$select->from('foo', '*');$select->where('bar = ?', 'baz');$select->orWhere('id IN(?)', array(1, 2, 3);?>

GROUP BY分句

根据需要，可以多次使用group()方法给查询到的数据进行分组

<?php// 创建一个$db对象，调用SELECT方法.$select = $db->select();//// SELECT COUNT(id)//     FROM foo//     GROUP BY bar, baz//$select->from('foo', 'COUNT(id)');$select->group('bar');$select->group('baz');// 同样可以这样调用 group() 方法:$select->group('bar, baz');// 还可以:$select->group(array('bar', 'baz'));?>

HAVING 条件

当需要在查询结果中加入having条件时，可以使用having()方法。 这种方法与where()方法的功能一样。.

当你多次调用having（）方法时，各个having的条件会“并”在一起进行操作； 假如你需要实现“或 ”操作，可以使用orHaving()方法

<?php// 创建一个$db对象，调用SELECT方法.$select = $db->select();//// SELECT COUNT(id) AS count_id//     FROM foo//     GROUP BY bar, baz//     HAVING count_id > "1"//$select->from('foo', 'COUNT(id) AS count_id');$select->group('bar, baz');$select->having('count_id > ?', 1);?>

ORDER BY 分句

根据需要，可以多次使用order()方法给查询到的数据进行排序

<?php// 创建一个$db对象，调用SELECT方法.$select = $db->select();//// SELECT * FROM round_table//     ORDER BY noble_title DESC, first_name ASC//$select->from('round_table', '*');$select->order('noble_title DESC');$select->order('first_name');// 同样可以这样调用 order() 方法:$select->order('noble_title DESC, first_name');// 还可以:$select->order(array('noble_title DESC', 'first_name'));?>

通过总数和偏移量进行LIMIT限制

Zend_db_select可以支持数据库层的limit语句限制。对于一些数据库，例如mysql 和postgresql，实现这些是相对容易的，因为这些数据库本身就支持“limit：count” 语法。

对于其他一些数据库来说，例如微软的sqlserver和oracle，要实现limit功能 就不那么简单了，因为他们本身就根本不支持limit语句。MS-SQL有一个top语 句来实现，而oracle要实现limit功能，查询语句的写法就更特殊一些。由于 zend_db_select内在地工作的方式，我们可以重写select语句以在oracle中 实现上述开源数据库系统的limit功能。

要通过设定查询的总数和偏移量对返回的结果进行限制,可以使用limit()方法， 总数值和一个可选的偏移量作为调用该方法的参数。

<?php// 首先，一个简单的 "LIMIT :count"$select = $db->select();$select->from('foo', '*');$select->order('id');$select->limit(10);//// 在mysql/psotgreSql/SQLite,可以得到这样的语句：//// SELECT * FROM foo//     ORDER BY id ASC//     LIMIT 10//// 但是在Microsoft SQL下,可以得到这样的语句：//// SELECT TOP 10 * FROM FOO//     ORDER BY id ASC////// 现在, 是更复杂的 "LIMIT :count OFFSET :offset"方法$select = $db->select();$select->from('foo', '*');$select->order('id');$select->limit(10, 20);//// 在mysql/psotgreSql/SQLite,可以得到这样的语句：//// SELECT * FROM foo//     ORDER BY id ASC//     LIMIT 10 OFFSET 20//// 但是在Microsoft SQL下,由于不支持偏移量功能,可以得到这样sql语句://// SELECT * FROM (//     SELECT TOP 10 * FROM (//         SELECT TOP 30 * FROM foo ORDER BY id DESC//     ) ORDER BY id ASC// )//// Zend_Db_Adapter 可以自动的完成sql语句的动态创建.//?>

通过页数和总数进行LIMIT限制

Zend_db_select同样也提供了翻页的limit功能。假如你想要从结果中找到 特定“页数”的结果，使用limitPage()方法；将你需要的页数值和每页显示 的数据值数作为参数传过去即可.

<?php// 构造基础的select方法:$select = $db->select();$select->from('foo', '*');$select->order('id');// ... 限制到第三页,每页包括10行数据$select->limitPage(3, 10);//// 在MySQL/PostgreSQL/SQLite下, 可以得到://// SELECT * FROM foo//     ORDER BY id ASC//     LIMIT 10 OFFSET 20//?>

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Zend_Db_Profiler

Zend_Db Zend Framework手册 中文版

Zend_Db_Table

Comments

Posted by: Shah Mubashir on: 2010-03-08 06:51:59

Hi ZF Developer,

I am new to zend frame work and i am trying to develop a site using zend framework. I am having problem with the fetching of records at first hand. Meaning there are lots of problem which i am facing developing a site. My first problem is of fetching the data.

In my index page the records which i am trying to fetch will come from two tables. So there the $model->fetchall() is not helpful to me. I want to use the Zend_Db_Select to fetch the records from two tables. As it is said in the examples it can be achived by Zend_Db_Select. 

My question is in the model class which is extended from Zend_Db_Table_Abstract contains a Zend_Db_Select object or do i have to create it explicitly to execute my queries. If i have to explicitly make an object of Zend_Db_Select so how am i going to do that.

I am waiting for your answer. Please do reply

Regards,
Shah Mubashir Hussain.

Posted by: Raul Sandrea on: 2010-03-16 21:20:41

Greetings Shah,

To successfully make a query on 2 tables you need to create a Zend_Db_Select object (Zend_Db_Table works as an interface to single table operations).

The usage it's fairly simple, you create an adapter (you can check for the available adapters on the folder Zend/Db/Adapter of your ZF installation), then from that adapter use the method ->select() to create your select object, then add the tables names/schemas as needed.

A quick example could be:
$dbconn = New Zend_Db_Adapter_Pdo_Pgsql($conn); //a postgresql connection where $conn contains the host, username, password, etc for the connection

$select = $dbconn->select();
$select->from('table1',
array('column1', 'column2')
)
->from('table2',
array('column1', 'column2')
)
->where('condition') //if needed
....

I hope this helps.

Regards,
Raul Sandrea

Posted by: Shah Mubashir on: 2010-03-18 10:07:27

Thanks Raul Sandrea for your comment.

I will definitely try it out. 

Correct me if i am wrong. What u are suggesting is that i should replace my model class ( Application_Model_DbTable_xxx extends Zend_Db_Table_Abstract ) with 
yours( Application_Model_DbTable_xxx extends Zend_Db_Adapter_Pdo_Pgsql ).

Right.

And then i should create a select object and start using it.

Thanks again Raul Sandrea.

Posted by: Shah Mubashir Hussain on: 2010-03-21 17:18:33

Many Thanks Raul Sandrea, it worked. :)

This is how my class looks like now.

class Application_Model_DbTable_Albums extends Zend_Db_Adapter_Mysqli
{
protected $_name = 'albums';
private static $database;
private const $_option = array(
'host' => 'localhost',
'username' => 'root',
'password' => '',
'dbname' => 'xxxx');

public function __construct()
{
parent::__construct($this->_option);
$this->database = $this->select();
}
.
.
.
}

Posted by: Raul Sandrea on: 2010-04-05 20:01:43

Glad I could help =)

Posted by: Jeffery Fernandez on: 2010-04-13 23:35:39

I don't understand why there is no mention of setIntegrityCheck(false) when you are making a join statement. I spent hours trying to figure out why my join query was giving error of "Select query cannot join with another table".

Maybe the notes in the Zend_DB_Table chapter should be added to this one as it is relevant to join statements.

Posted by: Ernest Szulikowski on: 2010-06-06 11:19:50

Please Note:[\b]

The code similar to one in Example #20 can lead to SQL Injection! See http://www.zend.com/webinar/Framework/70170000000bEs9-webinar-secure-application-development-with-the-ZF-20100505.flv for more.

Posted by: Everaldo Ribeiro on: 2010-09-01 11:58:13

For to get the maximum ID inside a model this function runs perfectly.

/* This function returns the last insert ID */
public function lastInsertId(){
$row = $this->createRow();
$id = $this->_db->lastInsertId();
return $id;
}

Everaldo Ribeiro, Cientec - everaldoribeiro01@gmail.com

Posted by: Alexandr on: 2010-09-07 10:17:22

I wrote a class that transform an existing mysql query to Zend_Db_Table_Select statement.
Something like:

string(106) "SELECT * FROM table1 WHERE a = 'test' AND (b='test2' OR c='test3' AND (d = 'test4 )) AND 1=1"
 | |
 \ /
string(144) "$this->select()
    ->from('table1', '*')
    ->where("a = 'test'")
    ->where("b='test2' OR c='test3' AND (d = 'test4 )")
    ->where("1=1")"

code
Maybe someone will suit the same lazy as I am.