Home > Backend Development > PHP Tutorial > Simple use of PHP PDO

Simple use of PHP PDO

巴扎黑
Release: 2016-11-11 13:27:40
Original
1302 people have browsed it

Php code

PHP Simple use of PDO (query(), exec(), prepare(), Transaction, row lock)

<?php  
            #数据库连接  
            $dbtype = &#39;mysql&#39;;  
            $host = &#39;localhost&#39;;  
            $db = &#39;test&#39;;  
            $user = &#39;root&#39;;  
            $psw = &#39;19sucai&#39;;  
              
            $dsn = $dbtype . &#39;:host=&#39; . $host . &#39;;&#39; . &#39;dbname=&#39; . $db;  
              
            try {  
                $dbh = new PDO($dsn, $user, $psw, array(PDO::ATTR_PERSISTENT=>true));  
                echo &#39;连接成功<br>&#39;;  
            } catch(Exception $e) {  
                die(&#39;Connect Failed Message: &#39; . $e->getMessage());  
            }  
              
            #使用query函数查询  
            $sql = &#39;SELECT * FROM user&#39;;  
            $query = $dbh->query($sql);  
            $query->setFetchMode(PDO::FETCH_ASSOC);    //设置结果集返回格式,此处为关联数组,即不包含index下标  
            $rs = $query->fetchAll();  
            var_dump($rs);  
              
            #使用exec函数进行INSERT,UPDATE,DELETE,结果返回受影响的行数  
            $sql = &#39;INSERT INTO user (`userName`, `userPassword`, `userAge`) SELECT (MAX(userId) + 1), \&#39;123456\&#39;, 18 FROM user&#39;;    //插入一行用户数据,其中userName使用userId最大值+1  
            // $rs = $dbh->exec($sql);  
            // var_dump($rs) . &#39;<br>&#39;;  
              
            #使用prepareStatement进行CURD  
            $sql = &#39;SELECT * FROM user WHERE userId = ?&#39;;  
            $stmt = $dbh->prepare($sql);  
            $stmt->bindParam(1, $userId);    //绑定第一个参数值  
            $userId = 1;  
              
            $stmt->execute();  
            $stmt->setFetchMode(PDO::FETCH_ASSOC);  
            $rs = $stmt->fetchAll();  
            var_dump($rs);  
              
            #使用事务  
            try {  
                $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);    //设置错误模式,发生错误时抛出异常  
                $dbh->beginTransaction();  
                $sql1 = &#39;SELECT bookNum FROM book WHERE bookId = ? FOR UPDATE&#39;;    //此处加上行锁,可以对bookNum做一些判断,bookNum>1,才做下一步更新操作  
                $sql2 = &#39;UPDATE book SET bookNum=bookNum-1 WHERE bookId = ?&#39;;    //加上行锁后,如果user1在买书,并且user1的买书过程没有结束,user2就不能执行SELECT查询书籍数量的操作,这样就保证了不会出现只有1本书,却两个人同时买的状况  
                $stmt1 = $dbh->prepare($sql1);  
                $stmt2 = $dbh->prepare($sql2);  
                $stmt1->bindParam(1, $userId);  
                $stmt2->bindParam(1, $userId);  
                $userId = 1;  
                $stmt1->execute();  
                $stmt2->execute();  
                $dbh->commit();  
            } catch(Exception $e) {  
                $dbh->rollBack();  
                die(&#39;Transaction Error Message: &#39; . $e->getMessage());  
            }  
?>
Copy after login


Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template