封装pdo单例模式类

时间：2022-12-11 08:47:57

　　

<?php
/**
* MyPDO
* @author zk <1125035618@qq.com>
* @license http://www.sunbloger.com/
*/
class MyPDO
{
protected static $_instance = null;
protected $dbName = '';
protected $dsn;
protected $dbh;

/**
     * 构造
     *
     * @return MyPDO
*/
private function __construct($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset)
    {
try {
$this->dsn = 'mysql:host='.$dbHost.';dbname='.$dbName;
$this->dbh = new PDO($this->dsn, $dbUser, $dbPasswd);
$this->dbh->exec('SET character_set_connection='.$dbCharset.', character_set_results='.$dbCharset.', character_set_client=binary');
        } catch (PDOException $e) {
$this->outputError($e->getMessage());
        }
    }

/**
     * 防止克隆
     *
*/
private function __clone() {}

/**
     * Singleton instance
     *
     * @return Object
*/
public static function getInstance($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset)
    {
if (self::$_instance === null) {
            self::$_instance = new self($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset);
        }
return self::$_instance;
    }

/**
     * Query 查询
     *
     * @param String $strSql SQL语句
     * @param String $queryMode 查询方式(All or Row)
     * @param Boolean $debug
     * @return Array
*/
public function query($strSql, $queryMode = 'All', $debug = false)
    {
if ($debug === true) $this->debug($strSql);
$recordset = $this->dbh->query($strSql);
$this->getPDOError();
if ($recordset) {
$recordset->setFetchMode(PDO::FETCH_ASSOC);
if ($queryMode == 'All') {
$result = $recordset->fetchAll();
            } elseif ($queryMode == 'Row') {
$result = $recordset->fetch();
            }
        } else {
$result = null;
        }
return $result;
    }

/**
     * Update 更新
     *
     * @param String $table 表名
     * @param Array $arrayDataValue 字段与值
     * @param String $where 条件
     * @param Boolean $debug
     * @return Int
*/
public function update($table, $arrayDataValue, $where = '', $debug = false)
    {
$this->checkFields($table, $arrayDataValue);
if ($where) {
$strSql = '';
foreach ($arrayDataValue as $key => $value) {
$strSql .= ", `$key`='$value'";
            }
$strSql = substr($strSql, 1);
$strSql = "UPDATE `$table` SET $strSql WHERE $where";
        } else {
$strSql = "REPLACE INTO `$table` (`".implode('`,`', array_keys($arrayDataValue))."`) VALUES ('".implode("','", $arrayDataValue)."')";
        }
if ($debug === true) $this->debug($strSql);
$result = $this->dbh->exec($strSql);
$this->getPDOError();
return $result;
    }

/**
     * Insert 插入
     *
     * @param String $table 表名
     * @param Array $arrayDataValue 字段与值
     * @param Boolean $debug
     * @return Int
*/
public function insert($table, $arrayDataValue, $debug = false)
    {
$this->checkFields($table, $arrayDataValue);
$strSql = "INSERT INTO `$table` (`".implode('`,`', array_keys($arrayDataValue))."`) VALUES ('".implode("','", $arrayDataValue)."')";
if ($debug === true) $this->debug($strSql);
$result = $this->dbh->exec($strSql);
$this->getPDOError();
return $result;
    }

/**
     * Replace 覆盖方式插入
     *
     * @param String $table 表名
     * @param Array $arrayDataValue 字段与值
     * @param Boolean $debug
     * @return Int
*/
public function replace($table, $arrayDataValue, $debug = false)
    {
$this->checkFields($table, $arrayDataValue);
$strSql = "REPLACE INTO `$table`(`".implode('`,`', array_keys($arrayDataValue))."`) VALUES ('".implode("','", $arrayDataValue)."')";
if ($debug === true) $this->debug($strSql);
$result = $this->dbh->exec($strSql);
$this->getPDOError();
return $result;
    }

/**
     * Delete 删除
     *
     * @param String $table 表名
     * @param String $where 条件
     * @param Boolean $debug
     * @return Int
*/
public function delete($table, $where = '', $debug = false)
    {
if ($where == '') {
$this->outputError("'WHERE' is Null");
        } else {
$strSql = "DELETE FROM `$table` WHERE $where";
if ($debug === true) $this->debug($strSql);
$result = $this->dbh->exec($strSql);
$this->getPDOError();
return $result;
        }
    }

/**
     * execSql 执行SQL语句
     *
     * @param String $strSql
     * @param Boolean $debug
     * @return Int
*/
public function execSql($strSql, $debug = false)
    {
if ($debug === true) $this->debug($strSql);
$result = $this->dbh->exec($strSql);
$this->getPDOError();
return $result;
    }

/**
     * 获取字段最大值
     *
     * @param string $table 表名
     * @param string $field_name 字段名
     * @param string $where 条件
*/
public function getMaxValue($table, $field_name, $where = '', $debug = false)
    {
$strSql = "SELECT MAX(".$field_name.") AS MAX_VALUE FROM $table";
if ($where != '') $strSql .= " WHERE $where";
if ($debug === true) $this->debug($strSql);
$arrTemp = $this->query($strSql, 'Row');
$maxValue = $arrTemp["MAX_VALUE"];
if ($maxValue == "" || $maxValue == null) {
$maxValue = 0;
        }
return $maxValue;
    }

/**
     * 获取指定列的数量
     *
     * @param string $table
     * @param string $field_name
     * @param string $where
     * @param bool $debug
     * @return int
*/
public function getCount($table, $field_name, $where = '', $debug = false)
    {
$strSql = "SELECT COUNT($field_name) AS NUM FROM $table";
if ($where != '') $strSql .= " WHERE $where";
if ($debug === true) $this->debug($strSql);
$arrTemp = $this->query($strSql, 'Row');
return $arrTemp['NUM'];
    }

/**
     * 获取表引擎
     *
     * @param String $dbName 库名
     * @param String $tableName 表名
     * @param Boolean $debug
     * @return String
*/
public function getTableEngine($dbName, $tableName)
    {
$strSql = "SHOW TABLE STATUS FROM $dbName WHERE Name='".$tableName."'";
$arrayTableInfo = $this->query($strSql);
$this->getPDOError();
return $arrayTableInfo[0]['Engine'];
    }

/**
     * beginTransaction 事务开始
*/
private function beginTransaction()
    {
$this->dbh->beginTransaction();
    }

/**
     * commit 事务提交
*/
private function commit()
    {
$this->dbh->commit();
    }

/**
     * rollback 事务回滚
*/
private function rollback()
    {
$this->dbh->rollback();
    }

/**
     * transaction 通过事务处理多条SQL语句
     * 调用前需通过getTableEngine判断表引擎是否支持事务
     *
     * @param array $arraySql
     * @return Boolean
*/
public function execTransaction($arraySql)
    {
$retval = 1;
$this->beginTransaction();
foreach ($arraySql as $strSql) {
if ($this->execSql($strSql) == 0) $retval = 0;
        }
if ($retval == 0) {
$this->rollback();
return false;
        } else {
$this->commit();
return true;
        }
    }

/**
     * checkFields 检查指定字段是否在指定数据表中存在
     *
     * @param String $table
     * @param array $arrayField
*/
private function checkFields($table, $arrayFields)
    {
$fields = $this->getFields($table);
foreach ($arrayFields as $key => $value) {
if (!in_array($key, $fields)) {
$this->outputError("Unknown column `$key` in field list.");
            }
        }
    }

/**
     * getFields 获取指定数据表中的全部字段名
     *
     * @param String $table 表名
     * @return array
*/
private function getFields($table)
    {
$fields = array();
$recordset = $this->dbh->query("SHOW COLUMNS FROM $table");
$this->getPDOError();
$recordset->setFetchMode(PDO::FETCH_ASSOC);
$result = $recordset->fetchAll();
foreach ($result as $rows) {
$fields[] = $rows['Field'];
        }
return $fields;
    }

/**
     * getPDOError 捕获PDO错误信息
*/
private function getPDOError()
    {
if ($this->dbh->errorCode() != '00000') {
$arrayError = $this->dbh->errorInfo();
$this->outputError($arrayError[2]);
        }
    }

/**
     * debug
     *
     * @param mixed $debuginfo
*/
private function debug($debuginfo)
    {
var_dump($debuginfo);
exit();
    }

/**
     * 输出错误信息
     *
     * @param String $strErrMsg
*/
private function outputError($strErrMsg)
    {
throw new Exception('MySQL Error: '.$strErrMsg);
    }

/**
     * destruct 关闭数据库连接
*/
public function destruct()
    {
$this->dbh = null;
    }
}
?>
 PHP调用方法: 
<?php
require 'MyPDO.class.php';
$db = MyPDO::getInstance('localhost', 'root', 'root', 'test', 'utf8');

//do something...

$db->destruct();
?>
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