php pdo對象使用詳解: 連接數據庫與exec方法

要使用pdo，首先需要開啟pdo擴展，我這里已經開啟了mysql的pdo擴展

ghostwu@dev:~$ php -m | grep pdo
pdo_mysql
ghostwu@dev:~$ 

１，連接數據庫

mysql> show create database shop \G;
*************************** 1. row ***************************
       Database: shop
Create Database: CREATE DATABASE `shop` /*!40100 DEFAULT CHARACTER SET utf8 */
1 row in set (0.00 sec)

mysql> show create table account \G;
*************************** 1. row ***************************
       Table: account
Create Table: CREATE TABLE `account` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(20) CHARACTER SET latin1 NOT NULL,
  `user_pwd` varchar(40) CHARACTER SET latin1 NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8

try{
        $dsn = 'mysql:host=localhost;dbname=shop';
        $username = 'root';
        $pwd = 'root';
        $pdo = new PDO( $dsn, $username, $pwd );
        var_dump( $pdo );
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }

>上面為參數形式連接數據庫

>uri形式連接數據庫

dsn.txt

mysql:host=localhost;dbname=shop;

try{
        $dsn = 'uri:file:///home/ghostwu/php/php2/pdo/dsn.txt';
        $username = 'root';
        $pwd = 'root';
        $pdo = new PDO( $dsn, $username, $pwd );
        var_dump( $pdo );
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }

還有一種是php.ini中寫dsn連接信息，不太推薦使用

２，exec執行一條sql語句，返回值為受影響的行數，如果沒有受影響的行數，返回值為0，該方法對select語句無效

try{
        $dsn = 'mysql:host=localhost;dbname=shop';
        $username = 'root';
        $pwd = 'root';
        $pdo = new PDO( $dsn, $username, $pwd );

        $sql =<<< SQL
        create table if not exists user(
        id int unsigned not null auto_increment,
        username varchar( 20 ) not null unique,
        pwd char( 32 ) not null,
        email varchar( 30 ) not null,
        primary key( id )    
        )engine myisam;
SQL;
        $res = $pdo->exec( $sql );
        var_dump( $res );
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }

３，執行insert語句

$insertUserSql = "insert into user( username, pwd, email ) values( 'ghostwu'," . "'" . md5( 'ghostwu' )  . "'" . ",'[e-mail]')";
        $res = $pdo->exec( $insertUserSql );
        var_dump( $res );

４，一次性執行多條sql語句

try{
        $dsn = 'mysql:host=localhost;dbname=shop';
        $username = 'root';
        $pwd = 'root';
        $pdo = new PDO( $dsn, $username, $pwd );
        $bajie = md5( 'bajie' );
        $wukong = md5( 'wukong' );
        $tangsheng = md5( 'tangsheng' );
        $insertUserSql =<<<EOF
        insert into user( username, pwd, email ) values( 'wukong', '$wukong', '[e-mail]' ),( 'bajie', '$bajie','[e-mail]' ),( 'tangsheng', '$tangsheng','[e-mail]' );
EOF;
        $res = $pdo->exec( $insertUserSql );
        var_dump( $res );
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }

５，獲取最后一次插入數據的自增id

    try{
        $dsn = 'mysql:host=localhost;dbname=shop';
        $username = 'root';
        $pwd = 'root';
        $pdo = new PDO( $dsn, $username, $pwd );
        $insertUserSql = "insert into user( username, pwd, email ) values( 'zhanzhao'," . "'" . md5('zhanzhao' ) . "','[e-mail]')";
        echo $insertUserSql . PHP_EOL;
        $res = $pdo->exec( $insertUserSql );
        echo $pdo->lastInsertId() . PHP_EOL;
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }

６，執行delete語句

try{
        $pdo = new PDO( "mysql:host=localhost;dbname=shop", 'root', 'root' );
        $sql = "delete from user where id = 1";
        $res = $pdo->exec( $sql );
        var_dump( $res );
    }catch( PDOException $e ) {
        echo $e->getMessage();
    }