<"htmlcode">

<"htmlcode">

<"htmlcode">

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：


<"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])) {
        $unsigned = true;
      }
      if (preg_match('/^(("LIMIT argument count=$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


<"$key=$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('/(("htmlcode">

<"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" 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 = '" 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 $cond an int"'" . addcslashes($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('/^(
             [+-]"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('"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：


<"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";
}




结果为：


成功插入新的记录！
新记录的ID值为：13
其内容为：
id值为：13
username值为：Jiqing
password值为：jiqing90061234




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。
更多关于zend相关内容感兴趣的读者可查看本站专题：《Zend FrameWork框架入门教程》、《php优秀开发框架总结》、《Yii框架入门及常用技巧总结》、《ThinkPHP入门教程》、《php面向对象程序设计入门教程》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》
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。

                                
                                

                                    Zend,Framework,Zend_Db,数据库操作