Question

<?php
    $hostname = "localhost";

    $username = "ODBC";

    $password = "";

    $dbname = "db_students";

    try{
        $dbh = new PDO("mysql:host=$hostname;dbname=$dbname",$username,$password);

        echo"Connected to database"."<br/>";

        $dbh->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);

        $stmt = $dbh->prepare("DELETE FROM enrolments
                WHERE student_name = :name");

        $stmt->bindParam(":name",$name,PDO::PARAM_STR,255);

        $name = "Pietie Kock";
        $stmt->execute();

        if($student_name > 0)
        {
           echo "record deleted ". $student_name;
        }else{

           echo "record doesn't exist". $student_name;

            $dbh = null;
            }catch(PDOException $e){
            echo $e->getMessage();
            }
        ?>

Answer 1

您的代码中未定义

$student_name要检查受上一个SQL语句影响的行数，我们使用 rowCount()

$stmt->execute();
if ($stmt->rowCount > 0) {
        echo "record deleted " . $student_name;
    } else {

        echo "record doesn't exist" . $student_name;

        $dbh = null;
    }

您也忘了关闭try您的代码

try {
    $dbh = new PDO("mysql:host=$hostname;dbname=$dbname", $username, $password);

    echo"Connected to database" . "<br/>";

    $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $stmt = $dbh->prepare("DELETE FROM enrolments
                WHERE student_name = :name");

    $stmt->bindParam(":name", $name, PDO::PARAM_STR, 255);

    $name = "Pietie Kock";
    $stmt->execute();


    if ($stmt->rowCount > 0) {
        echo "record deleted " . $student_name;
    } else {

        echo "record doesn't exist" . $student_name;

        $dbh = null;
    }
} catch (PDOException $e) {// close you try
    echo $e->getMessage();
}

想要删除数据库中的名称n如果名称存在，则必须显示该名称

1 个答案: