Einführungs-Tutorial zum Zend Framework: Detaillierte Erläuterung des Datenbankbetriebs von Zend_Db

本文实例讲述了Zend Framework中Zend_Db数据库操作方法。分享给大家供大家参考，具体如下：

引言：Zend操作数据库通过Zend_Db_Adapter

它可以连接多种数据库，可以是DB2数据库、MySQli数据库、Oracle数据库。等等。

只需要配置相应的参数就可以了。

下面通过案例来展示一下其连接数据库的过程。

连接mysql数据库

代码：

<?php
require_once 'Zend/Db.php';
$params = array('host'=>'127.0.0.1',
  'username'=>'root',
  'password'=>'',
  'dbname'=>'test'
  );
$db = Zend_Db::factory('PDO_Mysql',$params);

点评：

这是连接mysql的代码案例，提供相应的参数就可以了。连接不同的数据库，提供不同的参数。下面是sqlite的例子

代码：

<?php
require_once 'Zend/Db.php';
$params = array('dbname'=>'test.mdb');
$db = Zend_Db::factory('PDO_Sqlite',$params);

点评：

sqlite明显参数不一样了，只需要提供数据库名字就可以了。
连接完数据库之后，就可以查询数据库信息以及操作数据库信息了。
如果查询呢？

下面是查询的代码案例：

<?php
require_once 'Zend/Db.php';
$params = array('host'=>'127.0.0.1',
  'username'=>'root',
  'password'=>'',
  'dbname'=>'test'
  );
$db = Zend_Db::factory('PDO_Mysql',$params);
$sql = $db->quoteInto('SELECT * FROM user WHERE id<?','5');
$result = $db->query($sql);  //执行SQL查询
$r_a = $result->fetchAll(); //返回结果数组
print_r($r_a);

点评：

执行完上述代码，就会展示出数据库中前五条记录的信息。

那么这其中的玄机是什么呢？

我们来看一下源码。

我们来看看Db.php中的factory方法

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))));
    print_r($adapterName);exit;
    /*
     * Load the adapter class. This throws an exception
     * if the specified class cannot be loaded.
     */
    if (!class_exists($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;
}

点评：这个方法就是核心了，代码量不多，但是作用很明确，它会通过你提供的两个参数，自动生成相应的数据库连接类的对象。具有一定的灵活性，机动性。

主要是其中的

$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);
}

这段代码会引入相应的数据库连接类，比如前面的两个例子，就是分别引入了Zend目录下Db目录下Adapter目录下Pdo目录下的mysql.php类。

不同的数据库，会引入不同的数据库文件。

我们来看看mysql.php类中的内容：

<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 * @version  $Id: Mysql.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';
/**
 * Class for connecting to MySQL databases and performing common operations.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 */
class Zend_Db_Adapter_Pdo_Mysql extends Zend_Db_Adapter_Pdo_Abstract
{
  /**
   * PDO type.
   *
   * @var string
   */
  protected $_pdoType = 'mysql';
  /**
   * Keys are UPPERCASE SQL datatypes or the constants
   * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
   *
   * Values are:
   * 0 = 32-bit integer
   * 1 = 64-bit integer
   * 2 = float or decimal
   *
   * @var array Associative array of datatypes to values 0, 1, or 2.
   */
  protected $_numericDataTypes = array(
    Zend_Db::INT_TYPE  => Zend_Db::INT_TYPE,
    Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
    Zend_Db::FLOAT_TYPE => Zend_Db::FLOAT_TYPE,
    'INT'        => Zend_Db::INT_TYPE,
    'INTEGER'      => Zend_Db::INT_TYPE,
    'MEDIUMINT'     => Zend_Db::INT_TYPE,
    'SMALLINT'      => Zend_Db::INT_TYPE,
    'TINYINT'      => Zend_Db::INT_TYPE,
    'BIGINT'       => Zend_Db::BIGINT_TYPE,
    'SERIAL'       => Zend_Db::BIGINT_TYPE,
    'DEC'        => Zend_Db::FLOAT_TYPE,
    'DECIMAL'      => Zend_Db::FLOAT_TYPE,
    'DOUBLE'       => Zend_Db::FLOAT_TYPE,
    'DOUBLE PRECISION'  => Zend_Db::FLOAT_TYPE,
    'FIXED'       => Zend_Db::FLOAT_TYPE,
    'FLOAT'       => Zend_Db::FLOAT_TYPE
  );
  /**
   * Override _dsn() and ensure that charset is incorporated in mysql
   * @see Zend_Db_Adapter_Pdo_Abstract::_dsn()
   */
  protected function _dsn()
  {
    $dsn = parent::_dsn();
    if (isset($this->_config['charset'])) {
      $dsn .= ';charset=' . $this->_config['charset'];
    }
    return $dsn;
  }
  /**
   * Creates a PDO object and connects to the database.
   *
   * @return void
   * @throws Zend_Db_Adapter_Exception
   */
  protected function _connect()
  {
    if ($this->_connection) {
      return;
    }
    if (!empty($this->_config['charset'])) {
      $initCommand = "SET NAMES '" . $this->_config['charset'] . "'";
      $this->_config['driver_options'][1002] = $initCommand; // 1002 = PDO::MYSQL_ATTR_INIT_COMMAND
    }
    parent::_connect();
  }
  /**
   * @return string
   */
  public function getQuoteIdentifierSymbol()
  {
    return "`";
  }
  /**
   * Returns a list of the tables in the database.
   *
   * @return array
   */
  public function listTables()
  {
    return $this->fetchCol('SHOW TABLES');
  }
  /**
   * Returns the column descriptions for a table.
   *
   * The return value is an associative array keyed by the column name,
   * as returned by the RDBMS.
   *
   * The value of each array element is an associative array
   * with the following keys:
   *
   * SCHEMA_NAME   => string; name of database or schema
   * TABLE_NAME    => string;
   * COLUMN_NAME   => string; column name
   * COLUMN_POSITION => number; ordinal position of column in table
   * DATA_TYPE    => string; SQL datatype name of column
   * DEFAULT     => string; default expression of column, null if none
   * NULLABLE     => boolean; true if column can have nulls
   * LENGTH      => number; length of CHAR/VARCHAR
   * SCALE      => number; scale of NUMERIC/DECIMAL
   * PRECISION    => number; precision of NUMERIC/DECIMAL
   * UNSIGNED     => boolean; unsigned property of an integer type
   * PRIMARY     => boolean; true if column is part of the primary key
   * PRIMARY_POSITION => integer; position of column in primary key
   * IDENTITY     => integer; true if column is auto-generated with unique values
   *
   * @param string $tableName
   * @param string $schemaName OPTIONAL
   * @return array
   */
  public function describeTable($tableName, $schemaName = null)
  {
    // @todo use INFORMATION_SCHEMA someday when MySQL's
    // implementation has reasonably good performance and
    // the version with this improvement is in wide use.
    if ($schemaName) {
      $sql = 'DESCRIBE ' . $this->quoteIdentifier("$schemaName.$tableName", true);
    } else {
      $sql = 'DESCRIBE ' . $this->quoteIdentifier($tableName, true);
    }
    $stmt = $this->query($sql);
    // Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
    $result = $stmt->fetchAll(Zend_Db::FETCH_NUM);
    $field  = 0;
    $type  = 1;
    $null  = 2;
    $key   = 3;
    $default = 4;
    $extra  = 5;
    $desc = array();
    $i = 1;
    $p = 1;
    foreach ($result as $row) {
      list($length, $scale, $precision, $unsigned, $primary, $primaryPosition, $identity)
        = array(null, null, null, null, false, null, false);
      if (preg_match('/unsigned/', $row[$type])) {
        $unsigned = true;
      }
      if (preg_match('/^((?:var)?char)\((\d+)\)/', $row[$type], $matches)) {
        $row[$type] = $matches[1];
        $length = $matches[2];
      } else if (preg_match('/^decimal\((\d+),(\d+)\)/', $row[$type], $matches)) {
        $row[$type] = 'decimal';
        $precision = $matches[1];
        $scale = $matches[2];
      } else if (preg_match('/^float\((\d+),(\d+)\)/', $row[$type], $matches)) {
        $row[$type] = 'float';
        $precision = $matches[1];
        $scale = $matches[2];
      } else if (preg_match('/^((?:big|medium|small|tiny)?int)\((\d+)\)/', $row[$type], $matches)) {
        $row[$type] = $matches[1];
        // The optional argument of a MySQL int type is not precision
        // or length; it is only a hint for display width.
      }
      if (strtoupper($row[$key]) == 'PRI') {
        $primary = true;
        $primaryPosition = $p;
        if ($row[$extra] == 'auto_increment') {
          $identity = true;
        } else {
          $identity = false;
        }
        ++$p;
      }
      $desc[$this->foldCase($row[$field])] = array(
        'SCHEMA_NAME'   => null, // @todo
        'TABLE_NAME'    => $this->foldCase($tableName),
        'COLUMN_NAME'   => $this->foldCase($row[$field]),
        'COLUMN_POSITION' => $i,
        'DATA_TYPE'    => $row[$type],
        'DEFAULT'     => $row[$default],
        'NULLABLE'     => (bool) ($row[$null] == 'YES'),
        'LENGTH'      => $length,
        'SCALE'      => $scale,
        'PRECISION'    => $precision,
        'UNSIGNED'     => $unsigned,
        'PRIMARY'     => $primary,
        'PRIMARY_POSITION' => $primaryPosition,
        'IDENTITY'     => $identity
      );
      ++$i;
    }
    return $desc;
  }
  /**
   * Adds an adapter-specific LIMIT clause to the SELECT statement.
   *
   * @param string $sql
   * @param integer $count
   * @param integer $offset OPTIONAL
   * @throws Zend_Db_Adapter_Exception
   * @return string
   */
   public function limit($sql, $count, $offset = 0)
   {
    $count = intval($count);
    if ($count <= 0) {
      /** @see Zend_Db_Adapter_Exception */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
    }
    $offset = intval($offset);
    if ($offset < 0) {
      /** @see Zend_Db_Adapter_Exception */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
    }
    $sql .= " LIMIT $count";
    if ($offset > 0) {
      $sql .= " OFFSET $offset";
    }
    return $sql;
  }
}

这里又引入了一个Abstract类，抽象类

<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 * @version  $Id: Abstract.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 * @see Zend_Db_Adapter_Abstract
 */
require_once 'Zend/Db/Adapter/Abstract.php';
/**
 * @see Zend_Db_Statement_Pdo
 */
require_once 'Zend/Db/Statement/Pdo.php';
/**
 * Class for connecting to SQL databases and performing common operations using PDO.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 */
abstract class Zend_Db_Adapter_Pdo_Abstract extends Zend_Db_Adapter_Abstract
{
  /**
   * Default class name for a DB statement.
   *
   * @var string
   */
  protected $_defaultStmtClass = 'Zend_Db_Statement_Pdo';
  /**
   * Creates a PDO DSN for the adapter from $this->_config settings.
   *
   * @return string
   */
  protected function _dsn()
  {
    // baseline of DSN parts
    $dsn = $this->_config;
    // don't pass the username, password, charset, persistent and driver_options in the DSN
    unset($dsn['username']);
    unset($dsn['password']);
    unset($dsn['options']);
    unset($dsn['charset']);
    unset($dsn['persistent']);
    unset($dsn['driver_options']);
    // use all remaining parts in the DSN
    foreach ($dsn as $key => $val) {
      $dsn[$key] = "$key=$val";
    }
    return $this->_pdoType . ':' . implode(';', $dsn);
  }
  /**
   * Creates a PDO object and connects to the database.
   *
   * @return void
   * @throws Zend_Db_Adapter_Exception
   */
  protected function _connect()
  {
    // if we already have a PDO object, no need to re-connect.
    if ($this->_connection) {
      return;
    }
    // get the dsn first, because some adapters alter the $_pdoType
    $dsn = $this->_dsn();
    // check for PDO extension
    if (!extension_loaded('pdo')) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception('The PDO extension is required for this adapter but the extension is not loaded');
    }
    // check the PDO driver is available
    if (!in_array($this->_pdoType, PDO::getAvailableDrivers())) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception('The ' . $this->_pdoType . ' driver is not currently installed');
    }
    // create PDO connection
    $q = $this->_profiler->queryStart('connect', Zend_Db_Profiler::CONNECT);
    // add the persistence flag if we find it in our config array
    if (isset($this->_config['persistent']) && ($this->_config['persistent'] == true)) {
      $this->_config['driver_options'][PDO::ATTR_PERSISTENT] = true;
    }
    try {
      $this->_connection = new PDO(
        $dsn,
        $this->_config['username'],
        $this->_config['password'],
        $this->_config['driver_options']
      );
      $this->_profiler->queryEnd($q);
      // set the PDO connection to perform case-folding on array keys, or not
      $this->_connection->setAttribute(PDO::ATTR_CASE, $this->_caseFolding);
      // always use exceptions.
      $this->_connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch (PDOException $e) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception($e->getMessage(), $e->getCode(), $e);
    }
  }
  /**
   * Test if a connection is active
   *
   * @return boolean
   */
  public function isConnected()
  {
    return ((bool) ($this->_connection instanceof PDO));
  }
  /**
   * Force the connection to close.
   *
   * @return void
   */
  public function closeConnection()
  {
    $this->_connection = null;
  }
  /**
   * Prepares an SQL statement.
   *
   * @param string $sql The SQL statement with placeholders.
   * @param array $bind An array of data to bind to the placeholders.
   * @return PDOStatement
   */
  public function prepare($sql)
  {
    $this->_connect();
    $stmtClass = $this->_defaultStmtClass;
    if (!class_exists($stmtClass)) {
      require_once 'Zend/Loader.php';
      Zend_Loader::loadClass($stmtClass);
    }
    $stmt = new $stmtClass($this, $sql);
    $stmt->setFetchMode($this->_fetchMode);
    return $stmt;
  }
  /**
   * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
   *
   * As a convention, on RDBMS brands that support sequences
   * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
   * from the arguments and returns the last id generated by that sequence.
   * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
   * returns the last value generated for such a column, and the table name
   * argument is disregarded.
   *
   * On RDBMS brands that don't support sequences, $tableName and $primaryKey
   * are ignored.
   *
   * @param string $tableName  OPTIONAL Name of table.
   * @param string $primaryKey OPTIONAL Name of primary key column.
   * @return string
   */
  public function lastInsertId($tableName = null, $primaryKey = null)
  {
    $this->_connect();
    return $this->_connection->lastInsertId();
  }
  /**
   * Special handling for PDO query().
   * All bind parameter names must begin with ':'
   *
   * @param string|Zend_Db_Select $sql The SQL statement with placeholders.
   * @param array $bind An array of data to bind to the placeholders.
   * @return Zend_Db_Statement_Pdo
   * @throws Zend_Db_Adapter_Exception To re-throw PDOException.
   */
  public function query($sql, $bind = array())
  {
    if (empty($bind) && $sql instanceof Zend_Db_Select) {
      $bind = $sql->getBind();
    }
    if (is_array($bind)) {
      foreach ($bind as $name => $value) {
        if (!is_int($name) && !preg_match('/^:/', $name)) {
          $newName = ":$name";
          unset($bind[$name]);
          $bind[$newName] = $value;
        }
      }
    }
    try {
      return parent::query($sql, $bind);
    } catch (PDOException $e) {
      /**
       * @see Zend_Db_Statement_Exception
       */
      require_once 'Zend/Db/Statement/Exception.php';
      throw new Zend_Db_Statement_Exception($e->getMessage(), $e->getCode(), $e);
    }
  }
  /**
   * Executes an SQL statement and return the number of affected rows
   *
   * @param mixed $sql The SQL statement with placeholders.
   *           May be a string or Zend_Db_Select.
   * @return integer   Number of rows that were modified
   *           or deleted by the SQL statement
   */
  public function exec($sql)
  {
    if ($sql instanceof Zend_Db_Select) {
      $sql = $sql->assemble();
    }
    try {
      $affected = $this->getConnection()->exec($sql);
      if ($affected === false) {
        $errorInfo = $this->getConnection()->errorInfo();
        /**
         * @see Zend_Db_Adapter_Exception
         */
        require_once 'Zend/Db/Adapter/Exception.php';
        throw new Zend_Db_Adapter_Exception($errorInfo[2]);
      }
      return $affected;
    } catch (PDOException $e) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception($e->getMessage(), $e->getCode(), $e);
    }
  }
  /**
   * Quote a raw string.
   *
   * @param string $value   Raw string
   * @return string      Quoted string
   */
  protected function _quote($value)
  {
    if (is_int($value) || is_float($value)) {
      return $value;
    }
    $this->_connect();
    return $this->_connection->quote($value);
  }
  /**
   * Begin a transaction.
   */
  protected function _beginTransaction()
  {
    $this->_connect();
    $this->_connection->beginTransaction();
  }
  /**
   * Commit a transaction.
   */
  protected function _commit()
  {
    $this->_connect();
    $this->_connection->commit();
  }
  /**
   * Roll-back a transaction.
   */
  protected function _rollBack() {
    $this->_connect();
    $this->_connection->rollBack();
  }
  /**
   * Set the PDO fetch mode.
   *
   * @todo Support FETCH_CLASS and FETCH_INTO.
   *
   * @param int $mode A PDO fetch mode.
   * @return void
   * @throws Zend_Db_Adapter_Exception
   */
  public function setFetchMode($mode)
  {
    //check for PDO extension
    if (!extension_loaded('pdo')) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception('The PDO extension is required for this adapter but the extension is not loaded');
    }
    switch ($mode) {
      case PDO::FETCH_LAZY:
      case PDO::FETCH_ASSOC:
      case PDO::FETCH_NUM:
      case PDO::FETCH_BOTH:
      case PDO::FETCH_NAMED:
      case PDO::FETCH_OBJ:
        $this->_fetchMode = $mode;
        break;
      default:
        /**
         * @see Zend_Db_Adapter_Exception
         */
        require_once 'Zend/Db/Adapter/Exception.php';
        throw new Zend_Db_Adapter_Exception("Invalid fetch mode '$mode' specified");
        break;
    }
  }
  /**
   * Check if the adapter supports real SQL parameters.
   *
   * @param string $type 'positional' or 'named'
   * @return bool
   */
  public function supportsParameters($type)
  {
    switch ($type) {
      case 'positional':
      case 'named':
      default:
        return true;
    }
  }
  /**
   * Retrieve server version in PHP style
   *
   * @return string
   */
  public function getServerVersion()
  {
    $this->_connect();
    try {
      $version = $this->_connection->getAttribute(PDO::ATTR_SERVER_VERSION);
    } catch (PDOException $e) {
      // In case of the driver doesn't support getting attributes
      return null;
    }
    $matches = null;
    if (preg_match('/((?:[0-9]{1,2}\.){1,3}[0-9]{1,2})/', $version, $matches)) {
      return $matches[1];
    } else {
      return null;
    }
  }
}

这个抽象类中又有另一个核心的抽象类。一些核心的方法都在这里

<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 * @version  $Id: Abstract.php 25229 2013-01-18 08:17:21Z frosch $
 */
/**
 * @see Zend_Db
 */
require_once 'Zend/Db.php';
/**
 * @see Zend_Db_Select
 */
require_once 'Zend/Db/Select.php';
/**
 * Class for connecting to SQL databases and performing common operations.
 *
 * @category  Zend
 * @package  Zend_Db
 * @subpackage Adapter
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license  http://framework.zend.com/license/new-bsd   New BSD License
 */
abstract class Zend_Db_Adapter_Abstract
{
  /**
   * User-provided configuration
   *
   * @var array
   */
  protected $_config = array();
  /**
   * Fetch mode
   *
   * @var integer
   */
  protected $_fetchMode = Zend_Db::FETCH_ASSOC;
  /**
   * Query profiler object, of type Zend_Db_Profiler
   * or a subclass of that.
   *
   * @var Zend_Db_Profiler
   */
  protected $_profiler;
  /**
   * Default class name for a DB statement.
   *
   * @var string
   */
  protected $_defaultStmtClass = 'Zend_Db_Statement';
  /**
   * Default class name for the profiler object.
   *
   * @var string
   */
  protected $_defaultProfilerClass = 'Zend_Db_Profiler';
  /**
   * Database connection
   *
   * @var object|resource|null
   */
  protected $_connection = null;
  /**
   * Specifies the case of column names retrieved in queries
   * Options
   * Zend_Db::CASE_NATURAL (default)
   * Zend_Db::CASE_LOWER
   * Zend_Db::CASE_UPPER
   *
   * @var integer
   */
  protected $_caseFolding = Zend_Db::CASE_NATURAL;
  /**
   * Specifies whether the adapter automatically quotes identifiers.
   * If true, most SQL generated by Zend_Db classes applies
   * identifier quoting automatically.
   * If false, developer must quote identifiers themselves
   * by calling quoteIdentifier().
   *
   * @var bool
   */
  protected $_autoQuoteIdentifiers = true;
  /**
   * Keys are UPPERCASE SQL datatypes or the constants
   * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
   *
   * Values are:
   * 0 = 32-bit integer
   * 1 = 64-bit integer
   * 2 = float or decimal
   *
   * @var array Associative array of datatypes to values 0, 1, or 2.
   */
  protected $_numericDataTypes = array(
    Zend_Db::INT_TYPE  => Zend_Db::INT_TYPE,
    Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
    Zend_Db::FLOAT_TYPE => Zend_Db::FLOAT_TYPE
  );
  /** Weither or not that object can get serialized
   *
   * @var bool
   */
  protected $_allowSerialization = true;
  /**
   * Weither or not the database should be reconnected
   * to that adapter when waking up
   *
   * @var bool
   */
  protected $_autoReconnectOnUnserialize = false;
  /**
   * Constructor.
   *
   * $config is an array of key/value pairs or an instance of Zend_Config
   * containing configuration options. These options are common to most adapters:
   *
   * dbname     => (string) The name of the database to user
   * username    => (string) Connect to the database as this username.
   * password    => (string) Password associated with the username.
   * host      => (string) What host to connect to, defaults to localhost
   *
   * Some options are used on a case-by-case basis by adapters:
   *
   * port      => (string) The port of the database
   * persistent   => (boolean) Whether to use a persistent connection or not, defaults to false
   * protocol    => (string) The network protocol, defaults to TCPIP
   * caseFolding  => (int) style of case-alteration used for identifiers
   * socket     => (string) The socket or named pipe that should be used
   *
   * @param array|Zend_Config $config An array or instance of Zend_Config having configuration data
   * @throws Zend_Db_Adapter_Exception
   */
  public function __construct($config)
  {
    /*
     * Verify that adapter parameters are in an array.
     */
    if (!is_array($config)) {
      /*
       * Convert Zend_Config argument to a plain array.
       */
      if ($config instanceof Zend_Config) {
        $config = $config->toArray();
      } else {
        /**
         * @see Zend_Db_Adapter_Exception
         */
        require_once 'Zend/Db/Adapter/Exception.php';
        throw new Zend_Db_Adapter_Exception('Adapter parameters must be in an array or a Zend_Config object');
      }
    }
    $this->_checkRequiredOptions($config);
    $options = array(
      Zend_Db::CASE_FOLDING      => $this->_caseFolding,
      Zend_Db::AUTO_QUOTE_IDENTIFIERS => $this->_autoQuoteIdentifiers,
      Zend_Db::FETCH_MODE       => $this->_fetchMode,
    );
    $driverOptions = array();
    /*
     * normalize the config and merge it with the defaults
     */
    if (array_key_exists('options', $config)) {
      // can't use array_merge() because keys might be integers
      foreach ((array) $config['options'] as $key => $value) {
        $options[$key] = $value;
      }
    }
    if (array_key_exists('driver_options', $config)) {
      if (!empty($config['driver_options'])) {
        // can't use array_merge() because keys might be integers
        foreach ((array) $config['driver_options'] as $key => $value) {
          $driverOptions[$key] = $value;
        }
      }
    }
    if (!isset($config['charset'])) {
      $config['charset'] = null;
    }
    if (!isset($config['persistent'])) {
      $config['persistent'] = false;
    }
    $this->_config = array_merge($this->_config, $config);
    $this->_config['options'] = $options;
    $this->_config['driver_options'] = $driverOptions;
    // obtain the case setting, if there is one
    if (array_key_exists(Zend_Db::CASE_FOLDING, $options)) {
      $case = (int) $options[Zend_Db::CASE_FOLDING];
      switch ($case) {
        case Zend_Db::CASE_LOWER:
        case Zend_Db::CASE_UPPER:
        case Zend_Db::CASE_NATURAL:
          $this->_caseFolding = $case;
          break;
        default:
          /** @see Zend_Db_Adapter_Exception */
          require_once 'Zend/Db/Adapter/Exception.php';
          throw new Zend_Db_Adapter_Exception('Case must be one of the following constants: '
            . 'Zend_Db::CASE_NATURAL, Zend_Db::CASE_LOWER, Zend_Db::CASE_UPPER');
      }
    }
    if (array_key_exists(Zend_Db::FETCH_MODE, $options)) {
      if (is_string($options[Zend_Db::FETCH_MODE])) {
        $constant = 'Zend_Db::FETCH_' . strtoupper($options[Zend_Db::FETCH_MODE]);
        if(defined($constant)) {
          $options[Zend_Db::FETCH_MODE] = constant($constant);
        }
      }
      $this->setFetchMode((int) $options[Zend_Db::FETCH_MODE]);
    }
    // obtain quoting property if there is one
    if (array_key_exists(Zend_Db::AUTO_QUOTE_IDENTIFIERS, $options)) {
      $this->_autoQuoteIdentifiers = (bool) $options[Zend_Db::AUTO_QUOTE_IDENTIFIERS];
    }
    // obtain allow serialization property if there is one
    if (array_key_exists(Zend_Db::ALLOW_SERIALIZATION, $options)) {
      $this->_allowSerialization = (bool) $options[Zend_Db::ALLOW_SERIALIZATION];
    }
    // obtain auto reconnect on unserialize property if there is one
    if (array_key_exists(Zend_Db::AUTO_RECONNECT_ON_UNSERIALIZE, $options)) {
      $this->_autoReconnectOnUnserialize = (bool) $options[Zend_Db::AUTO_RECONNECT_ON_UNSERIALIZE];
    }
    // create a profiler object
    $profiler = false;
    if (array_key_exists(Zend_Db::PROFILER, $this->_config)) {
      $profiler = $this->_config[Zend_Db::PROFILER];
      unset($this->_config[Zend_Db::PROFILER]);
    }
    $this->setProfiler($profiler);
  }
  /**
   * Check for config options that are mandatory.
   * Throw exceptions if any are missing.
   *
   * @param array $config
   * @throws Zend_Db_Adapter_Exception
   */
  protected function _checkRequiredOptions(array $config)
  {
    // we need at least a dbname
    if (! array_key_exists('dbname', $config)) {
      /** @see Zend_Db_Adapter_Exception */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'dbname' that names the database instance");
    }
    if (! array_key_exists('password', $config)) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'password' for login credentials");
    }
    if (! array_key_exists('username', $config)) {
      /**
       * @see Zend_Db_Adapter_Exception
       */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception("Configuration array must have a key for 'username' for login credentials");
    }
  }
  /**
   * Returns the underlying database connection object or resource.
   * If not presently connected, this initiates the connection.
   *
   * @return object|resource|null
   */
  public function getConnection()
  {
    $this->_connect();
    return $this->_connection;
  }
  /**
   * Returns the configuration variables in this adapter.
   *
   * @return array
   */
  public function getConfig()
  {
    return $this->_config;
  }
  /**
   * Set the adapter's profiler object.
   *
   * The argument may be a boolean, an associative array, an instance of
   * Zend_Db_Profiler, or an instance of Zend_Config.
   *
   * A boolean argument sets the profiler to enabled if true, or disabled if
   * false. The profiler class is the adapter's default profiler class,
   * Zend_Db_Profiler.
   *
   * An instance of Zend_Db_Profiler sets the adapter's instance to that
   * object. The profiler is enabled and disabled separately.
   *
   * An associative array argument may contain any of the keys 'enabled',
   * 'class', and 'instance'. The 'enabled' and 'instance' keys correspond to the
   * boolean and object types documented above. The 'class' key is used to name a
   * class to use for a custom profiler. The class must be Zend_Db_Profiler or a
   * subclass. The class is instantiated with no constructor arguments. The 'class'
   * option is ignored when the 'instance' option is supplied.
   *
   * An object of type Zend_Config may contain the properties 'enabled', 'class', and
   * 'instance', just as if an associative array had been passed instead.
   *
   * @param Zend_Db_Profiler|Zend_Config|array|boolean $profiler
   * @return Zend_Db_Adapter_Abstract Provides a fluent interface
   * @throws Zend_Db_Profiler_Exception if the object instance or class specified
   *     is not Zend_Db_Profiler or an extension of that class.
   */
  public function setProfiler($profiler)
  {
    $enabled     = null;
    $profilerClass  = $this->_defaultProfilerClass;
    $profilerInstance = null;
    if ($profilerIsObject = is_object($profiler)) {
      if ($profiler instanceof Zend_Db_Profiler) {
        $profilerInstance = $profiler;
      } else if ($profiler instanceof Zend_Config) {
        $profiler = $profiler->toArray();
      } else {
        /**
         * @see Zend_Db_Profiler_Exception
         */
        require_once 'Zend/Db/Profiler/Exception.php';
        throw new Zend_Db_Profiler_Exception('Profiler argument must be an instance of either Zend_Db_Profiler'
          . ' or Zend_Config when provided as an object');
      }
    }
    if (is_array($profiler)) {
      if (isset($profiler['enabled'])) {
        $enabled = (bool) $profiler['enabled'];
      }
      if (isset($profiler['class'])) {
        $profilerClass = $profiler['class'];
      }
      if (isset($profiler['instance'])) {
        $profilerInstance = $profiler['instance'];
      }
    } else if (!$profilerIsObject) {
      $enabled = (bool) $profiler;
    }
    if ($profilerInstance === null) {
      if (!class_exists($profilerClass)) {
        require_once 'Zend/Loader.php';
        Zend_Loader::loadClass($profilerClass);
      }
      $profilerInstance = new $profilerClass();
    }
    if (!$profilerInstance instanceof Zend_Db_Profiler) {
      /** @see Zend_Db_Profiler_Exception */
      require_once 'Zend/Db/Profiler/Exception.php';
      throw new Zend_Db_Profiler_Exception('Class ' . get_class($profilerInstance) . ' does not extend '
        . 'Zend_Db_Profiler');
    }
    if (null !== $enabled) {
      $profilerInstance->setEnabled($enabled);
    }
    $this->_profiler = $profilerInstance;
    return $this;
  }
  /**
   * Returns the profiler for this adapter.
   *
   * @return Zend_Db_Profiler
   */
  public function getProfiler()
  {
    return $this->_profiler;
  }
  /**
   * Get the default statement class.
   *
   * @return string
   */
  public function getStatementClass()
  {
    return $this->_defaultStmtClass;
  }
  /**
   * Set the default statement class.
   *
   * @return Zend_Db_Adapter_Abstract Fluent interface
   */
  public function setStatementClass($class)
  {
    $this->_defaultStmtClass = $class;
    return $this;
  }
  /**
   * Prepares and executes an SQL statement with bound data.
   *
   * @param mixed $sql The SQL statement with placeholders.
   *           May be a string or Zend_Db_Select.
   * @param mixed $bind An array of data to bind to the placeholders.
   * @return Zend_Db_Statement_Interface
   */
  public function query($sql, $bind = array())
  {
    // connect to the database if needed
    $this->_connect();
    // is the $sql a Zend_Db_Select object?
    if ($sql instanceof Zend_Db_Select) {
      if (empty($bind)) {
        $bind = $sql->getBind();
      }
      $sql = $sql->assemble();
    }
    // make sure $bind to an array;
    // don't use (array) typecasting because
    // because $bind may be a Zend_Db_Expr object
    if (!is_array($bind)) {
      $bind = array($bind);
    }
    // prepare and execute the statement with profiling
    $stmt = $this->prepare($sql);
    $stmt->execute($bind);
    // return the results embedded in the prepared statement object
    $stmt->setFetchMode($this->_fetchMode);
    return $stmt;
  }
  /**
   * Leave autocommit mode and begin a transaction.
   *
   * @return Zend_Db_Adapter_Abstract
   */
  public function beginTransaction()
  {
    $this->_connect();
    $q = $this->_profiler->queryStart('begin', Zend_Db_Profiler::TRANSACTION);
    $this->_beginTransaction();
    $this->_profiler->queryEnd($q);
    return $this;
  }
  /**
   * Commit a transaction and return to autocommit mode.
   *
   * @return Zend_Db_Adapter_Abstract
   */
  public function commit()
  {
    $this->_connect();
    $q = $this->_profiler->queryStart('commit', Zend_Db_Profiler::TRANSACTION);
    $this->_commit();
    $this->_profiler->queryEnd($q);
    return $this;
  }
  /**
   * Roll back a transaction and return to autocommit mode.
   *
   * @return Zend_Db_Adapter_Abstract
   */
  public function rollBack()
  {
    $this->_connect();
    $q = $this->_profiler->queryStart('rollback', Zend_Db_Profiler::TRANSACTION);
    $this->_rollBack();
    $this->_profiler->queryEnd($q);
    return $this;
  }
  /**
   * Inserts a table row with specified data.
   *
   * @param mixed $table The table to insert data into.
   * @param array $bind Column-value pairs.
   * @return int The number of affected rows.
   * @throws Zend_Db_Adapter_Exception
   */
  public function insert($table, array $bind)
  {
    // extract and quote col names from the array keys
    $cols = array();
    $vals = array();
    $i = 0;
    foreach ($bind as $col => $val) {
      $cols[] = $this->quoteIdentifier($col, true);
      if ($val instanceof Zend_Db_Expr) {
        $vals[] = $val->__toString();
        unset($bind[$col]);
      } else {
        if ($this->supportsParameters('positional')) {
          $vals[] = '?';
        } else {
          if ($this->supportsParameters('named')) {
            unset($bind[$col]);
            $bind[':col'.$i] = $val;
            $vals[] = ':col'.$i;
            $i++;
          } else {
            /** @see Zend_Db_Adapter_Exception */
            require_once 'Zend/Db/Adapter/Exception.php';
            throw new Zend_Db_Adapter_Exception(get_class($this) ." doesn't support positional or named binding");
          }
        }
      }
    }
    // build the statement
    $sql = "INSERT INTO "
       . $this->quoteIdentifier($table, true)
       . ' (' . implode(', ', $cols) . ') '
       . 'VALUES (' . implode(', ', $vals) . ')';
    // execute the statement and return the number of affected rows
    if ($this->supportsParameters('positional')) {
      $bind = array_values($bind);
    }
    $stmt = $this->query($sql, $bind);
    $result = $stmt->rowCount();
    return $result;
  }
  /**
   * Updates table rows with specified data based on a WHERE clause.
   *
   * @param mixed    $table The table to update.
   * @param array    $bind Column-value pairs.
   * @param mixed    $where UPDATE WHERE clause(s).
   * @return int     The number of affected rows.
   * @throws Zend_Db_Adapter_Exception
   */
  public function update($table, array $bind, $where = '')
  {
    /**
     * Build "col = ?" pairs for the statement,
     * except for Zend_Db_Expr which is treated literally.
     */
    $set = array();
    $i = 0;
    foreach ($bind as $col => $val) {
      if ($val instanceof Zend_Db_Expr) {
        $val = $val->__toString();
        unset($bind[$col]);
      } else {
        if ($this->supportsParameters('positional')) {
          $val = '?';
        } else {
          if ($this->supportsParameters('named')) {
            unset($bind[$col]);
            $bind[':col'.$i] = $val;
            $val = ':col'.$i;
            $i++;
          } else {
            /** @see Zend_Db_Adapter_Exception */
            require_once 'Zend/Db/Adapter/Exception.php';
            throw new Zend_Db_Adapter_Exception(get_class($this) ." doesn't support positional or named binding");
          }
        }
      }
      $set[] = $this->quoteIdentifier($col, true) . ' = ' . $val;
    }
    $where = $this->_whereExpr($where);
    /**
     * Build the UPDATE statement
     */
    $sql = "UPDATE "
       . $this->quoteIdentifier($table, true)
       . ' SET ' . implode(', ', $set)
       . (($where) ? " WHERE $where" : '');
    /**
     * Execute the statement and return the number of affected rows
     */
    if ($this->supportsParameters('positional')) {
      $stmt = $this->query($sql, array_values($bind));
    } else {
      $stmt = $this->query($sql, $bind);
    }
    $result = $stmt->rowCount();
    return $result;
  }
  /**
   * Deletes table rows based on a WHERE clause.
   *
   * @param mixed    $table The table to update.
   * @param mixed    $where DELETE WHERE clause(s).
   * @return int     The number of affected rows.
   */
  public function delete($table, $where = '')
  {
    $where = $this->_whereExpr($where);
    /**
     * Build the DELETE statement
     */
    $sql = "DELETE FROM "
       . $this->quoteIdentifier($table, true)
       . (($where) ? " WHERE $where" : '');
    /**
     * Execute the statement and return the number of affected rows
     */
    $stmt = $this->query($sql);
    $result = $stmt->rowCount();
    return $result;
  }
  /**
   * Convert an array, string, or Zend_Db_Expr object
   * into a string to put in a WHERE clause.
   *
   * @param mixed $where
   * @return string
   */
  protected function _whereExpr($where)
  {
    if (empty($where)) {
      return $where;
    }
    if (!is_array($where)) {
      $where = array($where);
    }
    foreach ($where as $cond => &$term) {
      // is $cond an int? (i.e. Not a condition)
      if (is_int($cond)) {
        // $term is the full condition
        if ($term instanceof Zend_Db_Expr) {
          $term = $term->__toString();
        }
      } else {
        // $cond is the condition with placeholder,
        // and $term is quoted into the condition
        $term = $this->quoteInto($cond, $term);
      }
      $term = '(' . $term . ')';
    }
    $where = implode(' AND ', $where);
    return $where;
  }
  /**
   * Creates and returns a new Zend_Db_Select object for this adapter.
   *
   * @return Zend_Db_Select
   */
  public function select()
  {
    return new Zend_Db_Select($this);
  }
  /**
   * Get the fetch mode.
   *
   * @return int
   */
  public function getFetchMode()
  {
    return $this->_fetchMode;
  }
  /**
   * Fetches all SQL result rows as a sequential array.
   * Uses the current fetchMode for the adapter.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed         $bind Data to bind into SELECT placeholders.
   * @param mixed         $fetchMode Override current fetch mode.
   * @return array
   */
  public function fetchAll($sql, $bind = array(), $fetchMode = null)
  {
    if ($fetchMode === null) {
      $fetchMode = $this->_fetchMode;
    }
    $stmt = $this->query($sql, $bind);
    $result = $stmt->fetchAll($fetchMode);
    return $result;
  }
  /**
   * Fetches the first row of the SQL result.
   * Uses the current fetchMode for the adapter.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed $bind Data to bind into SELECT placeholders.
   * @param mixed         $fetchMode Override current fetch mode.
   * @return mixed Array, object, or scalar depending on fetch mode.
   */
  public function fetchRow($sql, $bind = array(), $fetchMode = null)
  {
    if ($fetchMode === null) {
      $fetchMode = $this->_fetchMode;
    }
    $stmt = $this->query($sql, $bind);
    $result = $stmt->fetch($fetchMode);
    return $result;
  }
  /**
   * Fetches all SQL result rows as an associative array.
   *
   * The first column is the key, the entire row array is the
   * value. You should construct the query to be sure that
   * the first column contains unique values, or else
   * rows with duplicate values in the first column will
   * overwrite previous data.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed $bind Data to bind into SELECT placeholders.
   * @return array
   */
  public function fetchAssoc($sql, $bind = array())
  {
    $stmt = $this->query($sql, $bind);
    $data = array();
    while ($row = $stmt->fetch(Zend_Db::FETCH_ASSOC)) {
      $tmp = array_values(array_slice($row, 0, 1));
      $data[$tmp[0]] = $row;
    }
    return $data;
  }
  /**
   * Fetches the first column of all SQL result rows as an array.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed $bind Data to bind into SELECT placeholders.
   * @return array
   */
  public function fetchCol($sql, $bind = array())
  {
    $stmt = $this->query($sql, $bind);
    $result = $stmt->fetchAll(Zend_Db::FETCH_COLUMN, 0);
    return $result;
  }
  /**
   * Fetches all SQL result rows as an array of key-value pairs.
   *
   * The first column is the key, the second column is the
   * value.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed $bind Data to bind into SELECT placeholders.
   * @return array
   */
  public function fetchPairs($sql, $bind = array())
  {
    $stmt = $this->query($sql, $bind);
    $data = array();
    while ($row = $stmt->fetch(Zend_Db::FETCH_NUM)) {
      $data[$row[0]] = $row[1];
    }
    return $data;
  }
  /**
   * Fetches the first column of the first row of the SQL result.
   *
   * @param string|Zend_Db_Select $sql An SQL SELECT statement.
   * @param mixed $bind Data to bind into SELECT placeholders.
   * @return string
   */
  public function fetchOne($sql, $bind = array())
  {
    $stmt = $this->query($sql, $bind);
    $result = $stmt->fetchColumn(0);
    return $result;
  }
  /**
   * Quote a raw string.
   *
   * @param string $value   Raw string
   * @return string      Quoted string
   */
  protected function _quote($value)
  {
    if (is_int($value)) {
      return $value;
    } elseif (is_float($value)) {
      return sprintf('%F', $value);
    }
    return "'" . addcslashes($value, "\000\n\r\\'\"\032") . "'";
  }
  /**
   * Safely quotes a value for an SQL statement.
   *
   * If an array is passed as the value, the array values are quoted
   * and then returned as a comma-separated string.
   *
   * @param mixed $value The value to quote.
   * @param mixed $type OPTIONAL the SQL datatype name, or constant, or null.
   * @return mixed An SQL-safe quoted value (or string of separated values).
   */
  public function quote($value, $type = null)
  {
    $this->_connect();
    if ($value instanceof Zend_Db_Select) {
      return '(' . $value->assemble() . ')';
    }
    if ($value instanceof Zend_Db_Expr) {
      return $value->__toString();
    }
    if (is_array($value)) {
      foreach ($value as &$val) {
        $val = $this->quote($val, $type);
      }
      return implode(', ', $value);
    }
    if ($type !== null && array_key_exists($type = strtoupper($type), $this->_numericDataTypes)) {
      $quotedValue = '0';
      switch ($this->_numericDataTypes[$type]) {
        case Zend_Db::INT_TYPE: // 32-bit integer
          $quotedValue = (string) intval($value);
          break;
        case Zend_Db::BIGINT_TYPE: // 64-bit integer
          // ANSI SQL-style hex literals (e.g. x'[\dA-F]+')
          // are not supported here, because these are string
          // literals, not numeric literals.
          if (preg_match('/^(
             [+-]?         # optional sign
             (?:
              0[Xx][\da-fA-F]+   # ODBC-style hexadecimal
              |\d+         # decimal or octal, or MySQL ZEROFILL decimal
              (?:[eE][+-]?\d+)?  # optional exponent on decimals or octals
             )
            )/x',
            (string) $value, $matches)) {
            $quotedValue = $matches[1];
          }
          break;
        case Zend_Db::FLOAT_TYPE: // float or decimal
          $quotedValue = sprintf('%F', $value);
      }
      return $quotedValue;
    }
    return $this->_quote($value);
  }
  /**
   * Quotes a value and places into a piece of text at a placeholder.
   *
   * The placeholder is a question-mark; all placeholders will be replaced
   * with the quoted value.  For example:
   *
   * <code>
   * $text = "WHERE date < ?";
   * $date = "2005-01-02";
   * $safe = $sql->quoteInto($text, $date);
   * // $safe = "WHERE date < '2005-01-02'"
   * </code>
   *
   * @param string $text The text with a placeholder.
   * @param mixed  $value The value to quote.
   * @param string $type OPTIONAL SQL datatype
   * @param integer $count OPTIONAL count of placeholders to replace
   * @return string An SQL-safe quoted value placed into the original text.
   */
  public function quoteInto($text, $value, $type = null, $count = null)
  {
    if ($count === null) {
      return str_replace('?', $this->quote($value, $type), $text);
    } else {
      while ($count > 0) {
        if (strpos($text, '?') !== false) {
          $text = substr_replace($text, $this->quote($value, $type), strpos($text, '?'), 1);
        }
        --$count;
      }
      return $text;
    }
  }
  /**
   * Quotes an identifier.
   *
   * Accepts a string representing a qualified indentifier. For Example:
   * <code>
   * $adapter->quoteIdentifier('myschema.mytable')
   * </code>
   * Returns: "myschema"."mytable"
   *
   * Or, an array of one or more identifiers that may form a qualified identifier:
   * <code>
   * $adapter->quoteIdentifier(array('myschema','my.table'))
   * </code>
   * Returns: "myschema"."my.table"
   *
   * The actual quote character surrounding the identifiers may vary depending on
   * the adapter.
   *
   * @param string|array|Zend_Db_Expr $ident The identifier.
   * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
   * @return string The quoted identifier.
   */
  public function quoteIdentifier($ident, $auto=false)
  {
    return $this->_quoteIdentifierAs($ident, null, $auto);
  }
  /**
   * Quote a column identifier and alias.
   *
   * @param string|array|Zend_Db_Expr $ident The identifier or expression.
   * @param string $alias An alias for the column.
   * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
   * @return string The quoted identifier and alias.
   */
  public function quoteColumnAs($ident, $alias, $auto=false)
  {
    return $this->_quoteIdentifierAs($ident, $alias, $auto);
  }
  /**
   * Quote a table identifier and alias.
   *
   * @param string|array|Zend_Db_Expr $ident The identifier or expression.
   * @param string $alias An alias for the table.
   * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
   * @return string The quoted identifier and alias.
   */
  public function quoteTableAs($ident, $alias = null, $auto = false)
  {
    return $this->_quoteIdentifierAs($ident, $alias, $auto);
  }
  /**
   * Quote an identifier and an optional alias.
   *
   * @param string|array|Zend_Db_Expr $ident The identifier or expression.
   * @param string $alias An optional alias.
   * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
   * @param string $as The string to add between the identifier/expression and the alias.
   * @return string The quoted identifier and alias.
   */
  protected function _quoteIdentifierAs($ident, $alias = null, $auto = false, $as = ' AS ')
  {
    if ($ident instanceof Zend_Db_Expr) {
      $quoted = $ident->__toString();
    } elseif ($ident instanceof Zend_Db_Select) {
      $quoted = '(' . $ident->assemble() . ')';
    } else {
      if (is_string($ident)) {
        $ident = explode('.', $ident);
      }
      if (is_array($ident)) {
        $segments = array();
        foreach ($ident as $segment) {
          if ($segment instanceof Zend_Db_Expr) {
            $segments[] = $segment->__toString();
          } else {
            $segments[] = $this->_quoteIdentifier($segment, $auto);
          }
        }
        if ($alias !== null && end($ident) == $alias) {
          $alias = null;
        }
        $quoted = implode('.', $segments);
      } else {
        $quoted = $this->_quoteIdentifier($ident, $auto);
      }
    }
    if ($alias !== null) {
      $quoted .= $as . $this->_quoteIdentifier($alias, $auto);
    }
    return $quoted;
  }
  /**
   * Quote an identifier.
   *
   * @param string $value The identifier or expression.
   * @param boolean $auto If true, heed the AUTO_QUOTE_IDENTIFIERS config option.
   * @return string    The quoted identifier and alias.
   */
  protected function _quoteIdentifier($value, $auto=false)
  {
    if ($auto === false || $this->_autoQuoteIdentifiers === true) {
      $q = $this->getQuoteIdentifierSymbol();
      return ($q . str_replace("$q", "$q$q", $value) . $q);
    }
    return $value;
  }
  /**
   * Returns the symbol the adapter uses for delimited identifiers.
   *
   * @return string
   */
  public function getQuoteIdentifierSymbol()
  {
    return '"';
  }
  /**
   * Return the most recent value from the specified sequence in the database.
   * This is supported only on RDBMS brands that support sequences
   * (e.g. Oracle, PostgreSQL, DB2). Other RDBMS brands return null.
   *
   * @param string $sequenceName
   * @return string
   */
  public function lastSequenceId($sequenceName)
  {
    return null;
  }
  /**
   * Generate a new value from the specified sequence in the database, and return it.
   * This is supported only on RDBMS brands that support sequences
   * (e.g. Oracle, PostgreSQL, DB2). Other RDBMS brands return null.
   *
   * @param string $sequenceName
   * @return string
   */
  public function nextSequenceId($sequenceName)
  {
    return null;
  }
  /**
   * Helper method to change the case of the strings used
   * when returning result sets in FETCH_ASSOC and FETCH_BOTH
   * modes.
   *
   * This is not intended to be used by application code,
   * but the method must be public so the Statement class
   * can invoke it.
   *
   * @param string $key
   * @return string
   */
  public function foldCase($key)
  {
    switch ($this->_caseFolding) {
      case Zend_Db::CASE_LOWER:
        $value = strtolower((string) $key);
        break;
      case Zend_Db::CASE_UPPER:
        $value = strtoupper((string) $key);
        break;
      case Zend_Db::CASE_NATURAL:
      default:
        $value = (string) $key;
    }
    return $value;
  }
  /**
   * called when object is getting serialized
   * This disconnects the DB object that cant be serialized
   *
   * @throws Zend_Db_Adapter_Exception
   * @return array
   */
  public function __sleep()
  {
    if ($this->_allowSerialization == false) {
      /** @see Zend_Db_Adapter_Exception */
      require_once 'Zend/Db/Adapter/Exception.php';
      throw new Zend_Db_Adapter_Exception(get_class($this) ." is not allowed to be serialized");
    }
    $this->_connection = false;
    return array_keys(array_diff_key(get_object_vars($this), array('_connection'=>false)));
  }
  /**
   * called when object is getting unserialized
   *
   * @return void
   */
  public function __wakeup()
  {
    if ($this->_autoReconnectOnUnserialize == true) {
      $this->getConnection();
    }
  }
  /**
   * Abstract Methods
   */
  /**
   * Returns a list of the tables in the database.
   *
   * @return array
   */
  abstract public function listTables();
  /**
   * Returns the column descriptions for a table.
   *
   * The return value is an associative array keyed by the column name,
   * as returned by the RDBMS.
   *
   * The value of each array element is an associative array
   * with the following keys:
   *
   * SCHEMA_NAME => string; name of database or schema
   * TABLE_NAME => string;
   * COLUMN_NAME => string; column name
   * COLUMN_POSITION => number; ordinal position of column in table
   * DATA_TYPE  => string; SQL datatype name of column
   * DEFAULT   => string; default expression of column, null if none
   * NULLABLE  => boolean; true if column can have nulls
   * LENGTH   => number; length of CHAR/VARCHAR
   * SCALE    => number; scale of NUMERIC/DECIMAL
   * PRECISION  => number; precision of NUMERIC/DECIMAL
   * UNSIGNED  => boolean; unsigned property of an integer type
   * PRIMARY   => boolean; true if column is part of the primary key
   * PRIMARY_POSITION => integer; position of column in primary key
   *
   * @param string $tableName
   * @param string $schemaName OPTIONAL
   * @return array
   */
  abstract public function describeTable($tableName, $schemaName = null);
  /**
   * Creates a connection to the database.
   *
   * @return void
   */
  abstract protected function _connect();
  /**
   * Test if a connection is active
   *
   * @return boolean
   */
  abstract public function isConnected();
  /**
   * Force the connection to close.
   *
   * @return void
   */
  abstract public function closeConnection();
  /**
   * Prepare a statement and return a PDOStatement-like object.
   *
   * @param string|Zend_Db_Select $sql SQL query
   * @return Zend_Db_Statement|PDOStatement
   */
  abstract public function prepare($sql);
  /**
   * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
   *
   * As a convention, on RDBMS brands that support sequences
   * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
   * from the arguments and returns the last id generated by that sequence.
   * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
   * returns the last value generated for such a column, and the table name
   * argument is disregarded.
   *
   * @param string $tableName  OPTIONAL Name of table.
   * @param string $primaryKey OPTIONAL Name of primary key column.
   * @return string
   */
  abstract public function lastInsertId($tableName = null, $primaryKey = null);
  /**
   * Begin a transaction.
   */
  abstract protected function _beginTransaction();
  /**
   * Commit a transaction.
   */
  abstract protected function _commit();
  /**
   * Roll-back a transaction.
   */
  abstract protected function _rollBack();
  /**
   * Set the fetch mode.
   *
   * @param integer $mode
   * @return void
   * @throws Zend_Db_Adapter_Exception
   */
  abstract public function setFetchMode($mode);
  /**
   * Adds an adapter-specific LIMIT clause to the SELECT statement.
   *
   * @param mixed $sql
   * @param integer $count
   * @param integer $offset
   * @return string
   */
  abstract public function limit($sql, $count, $offset = 0);
  /**
   * Check if the adapter supports real SQL parameters.
   *
   * @param string $type 'positional' or 'named'
   * @return bool
   */
  abstract public function supportsParameters($type);
  /**
   * Retrieve server version in PHP style
   *
   * @return string
   */
  abstract public function getServerVersion();
}

到此，我已经晕了。你呢？？？

哈哈哈。。。

下面看一些简单的案例

插入数据到数据库：

<?php
require_once 'Zend/Db.php';
$params = array('host'=>'127.0.0.1',
  'username'=>'root',
  'password'=>'',
  'dbname'=>'test'
  );
$db = Zend_Db::factory('PDO_Mysql',$params);
$row = array(
  'username'=>'Jiqing',
  'password'=>'jiqing90061234'
  );
$table = 'user';
$res = $db->insert($table,$row);
if($res){
  echo "成功插入新的记录！";
  echo "<p>";
  $last_insert_id = $db->lastInsertId($table);
  echo "新记录的ID值为：";
  echo $last_insert_id;
  echo "<p>";
  echo "其内容为：";
  $sql = "select * from $table where id=$last_insert_id";
  $result = $db->fetchRow($sql);
  echo "<p>";
  foreach($result as $key=>$val){
    echo $key;
    echo "值为：";
    echo $val;
    echo "<p>";
  }
}else{
  echo "插入数据有误";
}

修改update方法

删除delete方法

都大同小异，首先连接数据库，然后填写相应参数，执行即可。

查询方法总结：

fetchAll()匹配查询结果，返回一个连续的数组。
fetchAssoc()匹配查询结果，返回一个联合的数组。
fetchCol()匹配结果的第一列，返回一个数组。
fetchOne()陪陪查询结果的第一列与第一行的值，返回一个字符串。
fetchRow()匹配查询结果的第一行，返回一个数组。

常用的是第一个和最后一个方法，其他的方法用的不是很多。

希望本文所述对大家基于Zend Framework框架的PHP程序设计有所帮助。

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