在Zend Framework中，对数据库的封装，主要采用了工厂模式和适配器模式。具体模式的说明，可以参考设计模式相关的文章。
主要有如下几个功能：
一、Zend_Db_Adapter
Zend_Db_Adapter是Zend Framework的数据库抽象层API, 你可以使用 Zend_Db_Adapter 连接和处理多种数据库,包括:Microsoft SQL Server,MySql,DB2等等.
Zend_Db_Adapter_Abstract是抽象基类，如果要扩展增加新的数据库操作，可以继承基类，实现相应的方法。
其中
Zend_Db_Adapter_Mysqli
Zend_Db_Adapter_Oracle
Zend_Db_Adapter_Sqlsrv
Zend_Db_Adapter_Db2
就是具体数据的实现。
二、Zend_Db_Statement
除了可以使用Zend_Db_Adapter提供的fetchAll，insert等等方法，你可以直接使用Statement对象执行查询语句或者或者结果集。Zend_Db_Statement 实现是基于PDOStatement 的
三、Zend_Db_Profiler
Zend_Db_Profiler 主要用于数据库调优
四、Zend_Db_Select
Zend_Db_Select是一个sql语句的构造类。它封装了用户生成sql语句的常用方法。相当于是一个抽象的sql语句构造器，你不用考虑数据库sql语句之间的差异。
五、Zend_Db_Table
Zend_Db_Table对数据表操作进行了封装。
六、Zend_Db_Table_Row
中文说明是:
Zend_Db_Table_Row是Zend Framework的行数据网关.通常来说,你不可以自己实例化Zend_Db_Table_Row, 而是通过调用Zend_Db_Table::find()方法或者Zend_Db_Table::fetchRow()方法将Zend_Db_Table_Row作为 结果数据返回过来.一旦你得到来一个Zend_Db_Table_Row对象,你可以修改记录值(体现为类的属性)然后 调用save()方法可以将更改保存到原表上.
简单的讲，
Zend_Db_Table_Row 保存的数据和数据表中保存的记录是一一对应的关系。
七、Zend_Db_Table_Rowset
中文说明是:
Zend_Db_Table_Rowset是 Zend_Db_Table_Row对象集合的迭代器.通常来说,你不可以自己实例化Zend_Db_Table_Rowset, 而是通过调用Zend_Db_Table::find()方法或者fetchAll()方法将Zend_Db_Table_Rowset作为 结果数据返回过来.接下来就可以遍历Zend_Db_Table_Row对象集合并进行修改.
八、Zend_Db_Table_Definition
用于描述关系结构和配置Zend_Db_Table 实例的
以下是涉及到的文件目录结构和文件
│ Exception.php│ Expr.php│ Profiler.php│ Select.php│ Statement.php│ Table.php│├─Adapter│ │ Abstract.php│ │ Db2.php│ │ Exception.php│ │ Mysqli.php│ │ Oracle.php│ │ Sqlsrv.php│ ││ ├─Db2│ │ Exception.php│ ││ ├─Mysqli│ │ Exception.php│ ││ ├─Oracle│ │ Exception.php│ ││ ├─Pdo│ │ │ Abstract.php│ │ │ Ibm.php│ │ │ Mssql.php│ │ │ Mysql.php│ │ │ Oci.php│ │ │ Pgsql.php│ │ │ Sqlite.php│ │ ││ │ └─Ibm│ │ Db2.php│ │ Ids.php│ ││ └─Sqlsrv│ Exception.php│├─Profiler│ Exception.php│ Firebug.php│ Query.php│├─Select│ Exception.php│├─Statement│ │ Db2.php│ │ Exception.php│ │ Interface.php│ │ Mysqli.php│ │ Oracle.php│ │ Pdo.php│ │ Sqlsrv.php│ ││ ├─Db2│ │ Exception.php│ ││ ├─Mysqli│ │ Exception.php│ ││ ├─Oracle│ │ Exception.php│ ││ ├─Pdo│ │ Ibm.php│ │ Oci.php│ ││ └─Sqlsrv│ Exception.php│└─Table │ Abstract.php │ Definition.php │ Exception.php │ Row.php │ Rowset.php │ Select.php │ ├─Row │ Abstract.php │ Exception.php │ ├─Rowset │ Abstract.php │ Exception.php │ └─Select Exception.php
<?php/** * Class for connecting to SQL databases and performing common operations. * * @category Zend * @package Zend_Db * @copyright Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd New BSD License */class Zend_Db{ /** * Use the PROFILER constant in the config of a Zend_Db_Adapter. */ const PROFILER = 'profiler'; /** * Use the CASE_FOLDING constant in the config of a Zend_Db_Adapter. */ const CASE_FOLDING = 'caseFolding'; /** * Use the FETCH_MODE constant in the config of a Zend_Db_Adapter. */ const FETCH_MODE = 'fetchMode'; /** * Use the AUTO_QUOTE_IDENTIFIERS constant in the config of a Zend_Db_Adapter. */ const AUTO_QUOTE_IDENTIFIERS = 'autoQuoteIdentifiers'; /** * Use the ALLOW_SERIALIZATION constant in the config of a Zend_Db_Adapter. */ const ALLOW_SERIALIZATION = 'allowSerialization'; /** * Use the AUTO_RECONNECT_ON_UNSERIALIZE constant in the config of a Zend_Db_Adapter. */ const AUTO_RECONNECT_ON_UNSERIALIZE = 'autoReconnectOnUnserialize'; /** * Use the INT_TYPE, BIGINT_TYPE, and FLOAT_TYPE with the quote() method. */ const INT_TYPE = 0; const BIGINT_TYPE = 1; const FLOAT_TYPE = 2; /** * PDO constant values discovered by this script result: * * $list = array( * 'PARAM_BOOL', 'PARAM_NULL', 'PARAM_INT', 'PARAM_STR', 'PARAM_LOB', * 'PARAM_STMT', 'PARAM_INPUT_OUTPUT', 'FETCH_LAZY', 'FETCH_ASSOC', * 'FETCH_NUM', 'FETCH_BOTH', 'FETCH_OBJ', 'FETCH_BOUND', * 'FETCH_COLUMN', 'FETCH_CLASS', 'FETCH_INTO', 'FETCH_FUNC', * 'FETCH_GROUP', 'FETCH_UNIQUE', 'FETCH_CLASSTYPE', 'FETCH_SERIALIZE', * 'FETCH_NAMED', 'ATTR_AUTOCOMMIT', 'ATTR_PREFETCH', 'ATTR_TIMEOUT', * 'ATTR_ERRMODE', 'ATTR_SERVER_VERSION', 'ATTR_CLIENT_VERSION', * 'ATTR_SERVER_INFO', 'ATTR_CONNECTION_STATUS', 'ATTR_CASE', * 'ATTR_CURSOR_NAME', 'ATTR_CURSOR', 'ATTR_ORACLE_NULLS', * 'ATTR_PERSISTENT', 'ATTR_STATEMENT_CLASS', 'ATTR_FETCH_TABLE_NAMES', * 'ATTR_FETCH_CATALOG_NAMES', 'ATTR_DRIVER_NAME', * 'ATTR_STRINGIFY_FETCHES', 'ATTR_MAX_COLUMN_LEN', 'ERRMODE_SILENT', * 'ERRMODE_WARNING', 'ERRMODE_EXCEPTION', 'CASE_NATURAL', * 'CASE_LOWER', 'CASE_UPPER', 'NULL_NATURAL', 'NULL_EMPTY_STRING', * 'NULL_TO_STRING', 'ERR_NONE', 'FETCH_ORI_NEXT', * 'FETCH_ORI_PRIOR', 'FETCH_ORI_FIRST', 'FETCH_ORI_LAST', * 'FETCH_ORI_ABS', 'FETCH_ORI_REL', 'CURSOR_FWDONLY', 'CURSOR_SCROLL', * 'ERR_CANT_MAP', 'ERR_SYNTAX', 'ERR_CONSTRAINT', 'ERR_NOT_FOUND', * 'ERR_ALREADY_EXISTS', 'ERR_NOT_IMPLEMENTED', 'ERR_MISMATCH', * 'ERR_TRUNCATED', 'ERR_DISCONNECTED', 'ERR_NO_PERM', * ); * * $const = array(); * foreach ($list as $name) { * $const[$name] = constant("PDO::$name"); * } * var_export($const); */ const ATTR_AUTOCOMMIT = 0; const ATTR_CASE = 8; const ATTR_CLIENT_VERSION = 5; const ATTR_CONNECTION_STATUS = 7; const ATTR_CURSOR = 10; const ATTR_CURSOR_NAME = 9; const ATTR_DRIVER_NAME = 16; const ATTR_ERRMODE = 3; const ATTR_FETCH_CATALOG_NAMES = 15; const ATTR_FETCH_TABLE_NAMES = 14; const ATTR_MAX_COLUMN_LEN = 18; const ATTR_ORACLE_NULLS = 11; const ATTR_PERSISTENT = 12; const ATTR_PREFETCH = 1; const ATTR_SERVER_INFO = 6; const ATTR_SERVER_VERSION = 4; const ATTR_STATEMENT_CLASS = 13; const ATTR_STRINGIFY_FETCHES = 17; const ATTR_TIMEOUT = 2; const CASE_LOWER = 2; const CASE_NATURAL = 0; const CASE_UPPER = 1; const CURSOR_FWDONLY = 0; const CURSOR_SCROLL = 1; const ERR_ALREADY_EXISTS = NULL; const ERR_CANT_MAP = NULL; const ERR_CONSTRAINT = NULL; const ERR_DISCONNECTED = NULL; const ERR_MISMATCH = NULL; const ERR_NO_PERM = NULL; const ERR_NONE = '00000'; const ERR_NOT_FOUND = NULL; const ERR_NOT_IMPLEMENTED = NULL; const ERR_SYNTAX = NULL; const ERR_TRUNCATED = NULL; const ERRMODE_EXCEPTION = 2; const ERRMODE_SILENT = 0; const ERRMODE_WARNING = 1; const FETCH_ASSOC = 2; const FETCH_BOTH = 4; const FETCH_BOUND = 6; const FETCH_CLASS = 8; const FETCH_CLASSTYPE = 262144; const FETCH_COLUMN = 7; const FETCH_FUNC = 10; const FETCH_GROUP = 65536; const FETCH_INTO = 9; const FETCH_LAZY = 1; const FETCH_NAMED = 11; const FETCH_NUM = 3; const FETCH_OBJ = 5; const FETCH_ORI_ABS = 4; const FETCH_ORI_FIRST = 2; const FETCH_ORI_LAST = 3; const FETCH_ORI_NEXT = 0; const FETCH_ORI_PRIOR = 1; const FETCH_ORI_REL = 5; const FETCH_SERIALIZE = 524288; const FETCH_UNIQUE = 196608; const NULL_EMPTY_STRING = 1; const NULL_NATURAL = 0; const NULL_TO_STRING = NULL; const PARAM_BOOL = 5; const PARAM_INPUT_OUTPUT = -2147483648; const PARAM_INT = 1; const PARAM_LOB = 3; const PARAM_NULL = 0; const PARAM_STMT = 4; const PARAM_STR = 2; /** * Factory for Zend_Db_Adapter_Abstract classes. * * First argument may be a string containing the base of the adapter class * name, e.g. 'Mysqli' corresponds to class Zend_Db_Adapter_Mysqli. This * name is currently case-insensitive, but is not ideal to rely on this behavior. * If your class is named 'My_Company_Pdo_Mysql', where 'My_Company' is the namespace * and 'Pdo_Mysql' is the adapter name, it is best to use the name exactly as it * is defined in the class. This will ensure proper use of the factory API. * * First argument may alternatively be an object of type Zend_Config. * The adapter class base name is read from the 'adapter' property. * The adapter config parameters are read from the 'params' property. * * Second argument is optional and may be an associative array of key-value * pairs. This is used as the argument to the adapter constructor. * * If the first argument is of type Zend_Config, it is assumed to contain * all parameters, and the second argument is ignored. * * @param mixed $adapter String name of base adapter class, or Zend_Config object. * @param mixed $config OPTIONAL; an array or Zend_Config object with adapter parameters. * @return Zend_Db_Adapter_Abstract * @throws Zend_Db_Exception */ public static function factory($adapter, $config = array()) { if ($config instanceof Zend_Config) { $config = $config->toArray(); } /* * Convert Zend_Config argument to plain string * adapter name and separate config object. */ if ($adapter instanceof Zend_Config) { if (isset($adapter->params)) { $config = $adapter->params->toArray(); } if (isset($adapter->adapter)) { $adapter = (string) $adapter->adapter; } else { $adapter = null; } } /* * Verify that adapter parameters are in an array. */ if (!is_array($config)) { /** * @see Zend_Db_Exception */ require_once 'Zend/Db/Exception.php'; throw new Zend_Db_Exception('Adapter parameters must be in an array or a Zend_Config object'); } /* * Verify that an adapter name has been specified. */ if (!is_string($adapter) || empty($adapter)) { /** * @see Zend_Db_Exception */ require_once 'Zend/Db/Exception.php'; throw new Zend_Db_Exception('Adapter name must be specified in a string'); } /* * Form full adapter class name */ $adapterNamespace = 'Zend_Db_Adapter'; if (isset($config['adapterNamespace'])) { if ($config['adapterNamespace'] != '') { $adapterNamespace = $config['adapterNamespace']; } unset($config['adapterNamespace']); } // Adapter no longer normalized- see http://framework.zend.com/issues/browse/ZF-5606 $adapterName = $adapterNamespace . '_'; $adapterName .= str_replace(' ', '_', ucwords(str_replace('_', ' ', strtolower($adapter)))); /* * Load the adapter class. This throws an exception * if the specified class cannot be loaded. */ if (!class_exists($adapterName)) { require_once 'Zend/Loader.php'; Zend_Loader::loadClass($adapterName); } /* * Create an instance of the adapter class. * Pass the config to the adapter class constructor. */ $dbAdapter = new $adapterName($config); /* * Verify that the object created is a descendent of the abstract adapter type. */ if (! $dbAdapter instanceof Zend_Db_Adapter_Abstract) { /** * @see Zend_Db_Exception */ require_once 'Zend/Db/Exception.php'; throw new Zend_Db_Exception("Adapter class '$adapterName' does not extend Zend_Db_Adapter_Abstract"); } return $dbAdapter; }}