How to use PDO to manage databases?

Concept: Database management is divided into write operations and query operations.

, that is, use PDO to implement the database increase and deletion and modification operation. During the operation process, we must consider the error treatment of SQL itself, and the operation processing of the results. .

Query operation, that is, obtaining corresponding data from the database by executing SQL instructions.

1. Initialize PDO, each operation requires PDO instantiation: encapsulated execution.

//创建pdo_function.php文件
<?php 
    //数据库连接，并且设置字符集为utf8
     function pdo_init()
     {
         $dns="mysql:host=localhost;port=3306;dbname=my_database";
         $user=&#39;root&#39;;pdo_function
         $pass=&#39;root&#39;;
         $pdo=@new PDO($dns,$user,$pass); 
         
         if(!$pdo)
         {
             exit("数据库连接问题");
         }
         $pdo->exec("set names utf8");
         echo "连接初始化数据库成功";
         return $pdo;

     }
?>

2.SQL Usually should be passed in from the outside. What is needed externally is only the result, regardless of the process, so secondary encapsulation must be considered during actual development. That is, SQL is passed in externally, executed internally and controls errors, and finally returns the result.

在pdo_function.php中
//对数据库进行写操作
     function pdo_exec($pdo,$sql)
     {
          $result=$pdo->exec($sql);
          if($result===false)
          {
              echo "SQL语句错误"."<br>";
              echo "SQL错误代码：".$pdo->errorcode()."<br>";
              echo "SQL错误编号：".$pdo->errorInfo()[2]."<br>";
              exit;
          }
          return $result;
     }
//对数据库进行读操作
     function pdo_query($pdo,$sql)
     {
         $statement=$pdo->query($sql);
         if($statement===false)
         {
            echo "SQL语句错误"."<br>";
            echo "SQL错误代码：".$pdo->errorcode()."<br>";
            echo "SQL错误编号：".$pdo->errorInfo()[2]."<br>";
            exit;
         }
         return $statement;
     }

3. Specific implementation of write operation

<?php
     require "pdo_function.php";
     $pdo=pdo_init();
     
     $sql="INSERT INTO `student` (`id`, `name`, `age`, `hobbby`) VALUES (&#39;6&#39;, &#39;白也&#39;, &#39;70&#39;, &#39;drinking&#39;)";
     
     $reult=pdo_exec($pdo,$sql);
     echo $reult."<br>";//输出产生影响的行数。
?>

4. Specific implementation of query operation

<?php
    require "pdo_function.php";
    $pdo=pdo_init();
    
    $sql="select * from `student`";
    
    $statement=pdo_query($pdo,$sql);

?>

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