Zend Framework入门教程之Zend_Db数据库操作详解
发布时间：2021-01-17 08:08:52 所属栏目：PHP 来源：互联网
导读：这篇文章主要介绍了Zend Framework入门教程之Zend_Db数据库操作,结合实例形式详细分析了Zend_Db_Adapter的功能及数据库操作的相关技巧,需要的朋友可以参考下
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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： '127.0.0.1','username'=>'root','password'=>'','dbname'=>'test'
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$db = Zend_Db::factory('PDO_Mysql',$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： '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： '127.0.0.1',$params);
$sql = $db->quoteInto('SELECT * FROM user WHERE idquery($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 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 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： 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,false,false);
if (preg_match('/unsigned/',$row[$type])) {
$unsigned = true;
}
if (preg_match('/^((?:var)?char)((d+))/',$row[$type],$matches)) {
$row[$type] = $matches[1];
$length = $matches[2];
} else if (preg_match('/^decimal((d+),(d+))/',$matches)) {
$row[$type] = 'decimal';
$precision = $matches[1];
$scale = $matches[2];
} else if (preg_match('/^float((d+),$matches)) {
$row[$type] = 'float';
$precision = $matches[1];
$scale = $matches[2];
} else if (preg_match('/^((?:big|medium|small|tiny)?int)((d+))/',$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;
}
}
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