Execute SQL statements in PDO-Mysql Tutorial-php.cn

Execute SQL statements in PDO

黄舟

Release： 2017-02-25 10:33:23

Original

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exec() method

#The exec() method returns the number of affected rows after execution. The syntax is as follows:

int PDO::exec(string statement)

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Parametersstatement is the SQL statement to be executed. This method returns the number of rows affected when executing the query and is typically used in INSERT, DELETE and UPDATE statements.

For example:

$dbms=&#39;mysql&#39;;//数据库类型
$dbName=&#39;admin&#39;;//使用的数据库
$user=&#39;root&#39;;//数据库连接用户名
$pwd=&#39;password&#39;;//数据库连接密码
$host=&#39;localhost&#39;;//数据库主机名
$dsn="$dbms:host=$host;port=3306;dbname=$dbName";
try{
$pdo=new PDO($dsn,$user,$pwd);//初始化一个PDO对象，就是创建了数据库连接对象$pdo
$query="insert into user(username,password) values(&#39;admin&#39;,&#39;123456&#39;)";//需要执行的sql语句
$res=$pdo->exec($query);//执行添加语句并返回受影响行数
echo "数据添加成功，受影响行数为： ".$res;
}catch(Exception $e){
die("Error!:".$e->getMessage().&#39;<br>&#39;);
}

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The running result is:

数据添加成功，受影响行数为：
 1

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query() method

query() method is used to return the result set after executing the query. The syntax is as follows

PDOStatement
 PDO::query(string statement)

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Parameter statement is the SQL statement to be executed. It returns a PDOStatement object

##For example:

$dbms=&#39;mysql&#39;;
$dbName=&#39;admin&#39;;
$user=&#39;root&#39;;
$pwd=&#39;905407339&#39;;
$host=&#39;localhost&#39;;
$dsn="$dbms:host=$host;port=3306;dbname=$dbName";
try{
$pdo=new PDO($dsn,$user,$pwd);
$query="select * from user";
$res=$pdo->query($query);
print_r($res);
}catch(Exception $e){
die("Error!:".$e->getMessage().&#39;<br>&#39;);
}

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##The running result is:

PDOStatement
 Object ( [queryString] => select * from user )

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If you want to see the specific results of the query, you can pass The foreach statement completes the loop output

For example:

foreach($res as $val){
echo $val[&#39;username&#39;]."----".$val[&#39;password&#39;].&#39;<br>&#39;;
}

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The running result is:

107lab----e10adc3949ba59abbe56e057f20f883e
admin----123456

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Note: If you want to see the detailed usage of foreach, please check: http:// www.php.cn/

query() and exec()

query可以实现所有exec的功能

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For example:

$dbms=&#39;mysql&#39;;//数据库类型
$dbName=&#39;admin&#39;;//使用的数据库
$user=&#39;root&#39;;//数据库连接用户名
$pwd=&#39;905407339&#39;;//数据库连接密码
$host=&#39;localhost&#39;;//数据库主机名
$dsn="$dbms:host=$host;port=3306;dbname=$dbName";
try{
$pdo=new PDO($dsn,$user,$pwd);//初始化一个PDO对象，就是创建了数据库连接对象$pdo
$query="insert into user(username,password) values(&#39;admin&#39;,&#39;123456&#39;)";//需要执行的sql语句
$res=$pdo->query($query);//执行添加语句并返回受影响行数
echo "数据添加成功，受影响行数为： ".$res->rowCount();
}catch(Exception $e){
die("Error!:".$e->getMessage().&#39;<br>&#39;);
}

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运行结果为：

数据添加成功，受影响行数为： 1

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注：

1、query和exec都可以执行所有的sql语句，只是返回值不同而已。

2、query可以实现所有exec的功能。

3、当把select语句应用到 exec 时，总是返回 0

预处理语句----prepare()语句和execute()语句

预处理语句包括prepare()和execute()两种方法。首先，通过prepare()方法做查询准备工作，然后通过execute()方法执行查询，并且还可以通过bindParam()方法来绑定参数给execute()方法，语法如下：

PDOStatement
 PDO::prepare(string statement[,array driver_options])
bool
 PDOStatement::execute([array input_parameters])

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例如：

在PDO中通过预处理语句prepare()和execute()执行SQL查询语句，并且应用while()语句和fetch()方法完成数据的循环输出

$dbms=&#39;mysql&#39;;//数据库类型
$dbName=&#39;admin&#39;;//使用的数据库
$user=&#39;root&#39;;//数据库连接用户名
$pwd=&#39;905407339&#39;;//数据库连接密码
$host=&#39;localhost&#39;;//数据库主机名
$dsn="$dbms:host=$host;port=3306;dbname=$dbName";
try{
    $pdo=new PDO($dsn,$user,$pwd);//初始化一个PDO对象，就是创建了数据库连接对象$pdo
    $query="select * from user";//需要执行的sql语句
    $res=$pdo->prepare($query);//准备查询语句
    $res->execute();
    while($result=$res->fetch(PDO::FETCH_ASSOC)){
        echo $result[&#39;id&#39;]." ".$result[&#39;username&#39;]." ".$result[&#39;password&#39;].&#39;<br>&#39;;
    }
}catch(Exception $e){
    die("Error!:".$e->getMessage().&#39;<br>&#39;);
}

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运行结果为：

1
 107lab e10adc3949ba59abbe56e057f20f883e
4 admin 123456
5 admin 123456

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关于PDO中获取结果集的方法正在创作阶段，敬请期待。

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Execute SQL statements in PDO