php:在运行INSERT查询之前检查变量是否不为空 [英] php: check if variable is not empty before running INSERT query

问题描述

我为我的婚礼网站构建了一个歌曲请求表单，并希望在POST'到数据库之前检查存储表单输入的变量是否为空.我的目标很简单，那就是防止在for触发时将空白行添加到mysql数据库中.

I built a song request form for my wedding website and would like to check if the variables I am storing the form input in is empty before POST'ing to the database. My goal is simple prevent blank rows from being added to mysql db when the for is fired off.

 <?php 
// extract data from form; store in variable
$artist =  $_POST["artist"];
$song = $_POST["song"];

// connect to server 
$conn = mysql_connect('host', 'user', 'pass');


// check if you can connect; if not then die

if (!$conn) {
    echo "<center>";
    die('Could Not Connect: ' . mysql_error());
    echo "</center>";
    }

// check if you can select table; in not then die

$db = mysql_select_db('database', $conn);

if (!$db) {
    echo "<center>";
    die('Database Not Selected: ' . mysql_error());
    echo "</center>";
    }

// Define the query to inser the song request
$insert = mysql_query("INSERT INTO Songs (Artist, Song) VALUES ('$artist', '$song')");  

// check if above variables are empty 
if (!empty($artist) and !empty($song)) {
    echo "<center>";
    echo "Insert was succesful<br>";
    echo "<a href='index.html' target='_self' >Back</a>";
    echo "</center>";
}
else {
    echo "<center>";
    die("Please fill in at least the artist name");
    echo "</center>";
}

// close the connection to the server
mysql_close($conn);
?>

我在一个名为insert.php的文件中具有以上内容，该文件在提交索引页上的表单时被触发.表单正在使用POST提交并且可以正常工作，但是我想防止空白提交的发生.

I have the above in a file called insert.php which is fired off when form on the index page is submitted. Form is submitting using POST and works just fine, however I would like to prevent blank submissions from happening.

对编程非常陌生，想学习如何正确地做到这一点.

Very new to programming and want to learn how to do this right.

感谢您的耐心等候.

推荐答案

您是如此亲密！所有您需要做的就是在检查歌手和歌曲是否填写完之后放上插入物！

You are so close! All you had to do was put the insert after you do a check if the artist and song are filled in!

<?php 
    // extract data from form; store in variable
    $artist =  $_POST["artist"];
    $song = $_POST["song"];

    // connect to server 
    $conn = mysql_connect('host', 'user', 'pass');

    // check if you can connect; if not then die

    if (!$conn) {
        echo "<center>";
        die('Could Not Connect: ' . mysql_error());
        echo "</center>";
    }

    // check if you can select table; in not then die

    $db = mysql_select_db('database', $conn);

    if (!$db) {
        echo "<center>";
        die('Database Not Selected: ' . mysql_error());
        echo "</center>";
    }

    // check if above variables are empty 
    if (!empty($artist) and !empty($song)) {
        // Define the query to inser the song request
        $insert = mysql_query("INSERT INTO Songs (Artist, Song) VALUES ('$artist', '$song')");  

        if($insert) {
          echo "<center>";
          echo "Insert was succesful<br>";
          echo "<a href='index.html' target='_self' >Back</a>";
          echo "</center>";
        }
    }
    else {
        echo "<center>";
        die("Please fill in at least the artist name");
        echo "</center>";
    }

    // close the connection to the server
    mysql_close($conn);

就是这样！

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