Zend_Db_Table_Definition is a class that can be used to describe the relationships and configuration options that should be used when Zend_Db_Table is used via concrete instantiation.

Zend_Db_Table_Definition  用于定義關(guān)聯(lián)關(guān)系和對(duì)實(shí)例化Zend_Db_Table的相關(guān)選項(xiàng)配置的類。

For all of the same options that are available when configuring an extendedZend_Db_Table_Abstract class, those options are also available when describing a definition file. 

 所有繼承實(shí)現(xiàn)Zend_Db_Table_Abstract 類的配置選項(xiàng),都是可以使用定義描述文件的。

This definition file should be passed to the class at instantiation time so that it can know the full definition of all tables in said definition.

通過(guò)在實(shí)例化時(shí)，將表的定義文件傳遞給類。

Below is a definition that will describe the table names and relationships between table objects. 

下面是表名和表對(duì)象之間的關(guān)聯(lián)關(guān)系的定義。

Note: if 'name' is left out of the definition, it will be taken as the key of the defined table (an example of this is in the 'genre' section in the example below.)

注：如果“name”的定義被省略了，將采用表定義的key值（例如下面的“genre”部分）。

$definition = new Zend_Db_Table_Definition(array(    'author' => array(        'name' => 'author',        'dependentTables' => array('book')        ),    'book' => array(        'name' => 'book',        'referenceMap' => array(            'author' => array(                'columns' => 'author_id',                'refTableClass' => 'author',                'refColumns' => 'id'                )            )        ),    'genre' => null,    'book_to_genre' => array(        'referenceMap' => array(            'book' => array(                'columns' => 'book_id',                'refTableClass' => 'book',                'refColumns' => 'id'                ),            'genre' => array(                'columns' => 'genre_id',                'refTableClass' => 'genre',                'refColumns' => 'id'                )            )        )    ));

As you can see, the same options you'd generally see inside of an extended Zend_Db_Table_Abstract class are documented in this array as well. 

正如你看到的，繼承實(shí)現(xiàn)Zend_Db_Table_Abstract類時(shí)相同的選項(xiàng)，也要在這個(gè)數(shù)組中定義。

When passed into  Zend_Db_Table constructor, this definition ispersisted to any tables it will need to create in order to return the proper rows.

當(dāng)傳入  Zend_Db_Table 構(gòu)造函數(shù)時(shí), 這個(gè)定義會(huì)被持久化到所有表中。它必須被創(chuàng)建目的是為了返回對(duì)應(yīng)的行 。

Below is an example of the primary table instantiation as well as thefindDependentRowset() and findManyToManyRowset() calls that will correspond to the data model described above:

下面是通過(guò)上面定義的主表實(shí)例化的例子，然后調(diào)用 findDependentRowset（）和 findManyToManyRowset（）方法：

$authorTable = new Zend_Db_Table('author', $definition);$authors = $authorTable->fetchAll(); foreach ($authors as $author) {    echo $author->id       . ': '       . $author->first_name       . ' '       . $author->last_name       . PHP_EOL;    $books = $author->findDependentRowset('book');    foreach ($books as $book) {        echo '    Book: ' . $book->title . PHP_EOL;        $genreOutputArray = array();        $genres = $book->findManyToManyRowset('genre', 'book_to_genre');        foreach ($genres as $genreRow) {            $genreOutputArray[] = $genreRow->name;        }        echo '        Genre: ' . implode(', ', $genreOutputArray) . PHP_EOL;    }}

Sometimes you want to use both paradigms for defining and using the table gateway: both by extension and concrete instantiation.To do this simply leave out any table configurations out of the definition. 

有時(shí)可能會(huì)同時(shí)使用Zend_Db_Table和 Zend_Db_Table_Definition。要做到這一點(diǎn)，只需實(shí)現(xiàn)所有表的定義，即可。

This will allow Zend_Db_Table to look for the actual refered class instead of the definition key.

允許采用Zend_Db_Table的具體類代替定義的KEY

Building on the example above, we will allow for one of the table configurations to be aZend_Db_Table_Abstract extended class, while keeping the rest of the tables as part of the definition. 

基于上面的例子, 我們可以配置其中一個(gè) 實(shí)例化Zend_Db_Table_Abstract 的類,   而其它的表保持原有定義。

We will also show how one would interact with this new definition.

以下是具體的定義。

class MyBook extends Zend_Db_Table_Abstract{    protected $_name = 'book';    protected $_referenceMap = array(        'author' => array(            'columns' => 'author_id',            'refTableClass' => 'author',            'refColumns' => 'id'            )        );} $definition = new Zend_Db_Table_Definition(array(    'author' => array(        'name' => 'author',        'dependentTables' => array('MyBook')        ),    'genre' => null,    'book_to_genre' => array(        'referenceMap' => array(            'book' => array(                'columns' => 'book_id',                'refTableClass' => 'MyBook',                'refColumns' => 'id'                ),            'genre' => array(                'columns' => 'genre_id',                'refTableClass' => 'genre',                'refColumns' => 'id'                )            )        )    )); $authorTable = new Zend_Db_Table('author', $definition);$authors = $authorTable->fetchAll(); foreach ($authors as $author) {    echo $author->id       . ': '       . $author->first_name       . ' '       . $author->last_name       . PHP_EOL;    $books = $author->findDependentRowset(new MyBook());    foreach ($books as $book) {        echo '    Book: ' . $book->title . PHP_EOL;        $genreOutputArray = array();        $genres = $book->findManyToManyRowset('genre', 'book_to_genre');        foreach ($genres as $genreRow) {            $genreOutputArray[] = $genreRow->name;        }        echo '        Genre: ' . implode(', ', $genreOutputArray) . PHP_EOL;    }}

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