php - 使用 php 和 mysql 的简单 html 表单。如何维护数据库中空字段的 NULL 值

Question

我构建了一个简单的 html 表单，其中包含输入框和文本区域，然后在 php 脚本的帮助下将其插入到 mysql 数据库中。并非所有字段都必须填写，我希望能够在数据库中搜索 NULL 字段。我的问题是，当表单提交时，即使没有信息的条目也会插入一些类似空白的内容，这意味着我无法在数据库中搜索 NULL 字段，因为会返回所有内容。

这是将 MYSQL 插入查询发送到数据库的 php 脚本

<?php
/*Av Tech Name*/
$techNam = $_POST['techNam'];
/* Building */
$building = $_POST['building'];
/* Room */ 
$roomNum = $_POST['roomNum'];
/* Day */
$day = $_POST['day'];
/*Month*/
$month = $_POST['month'];
/*Projector Power */
$projPower = $_POST['projPower'];
/* Screen decends and retracts */
$screenUpDown = $_POST['screenUpDown'];
/* Power to buton control */
$controlPower = $_POST['controlPower'];
/* Lamp working */
$projLamp = $_POST['projLamp'];
/* Rips and tears to the screen */
$rips = $_POST['rips'];
/* Control Functions */
$controlFunctions = $_POST['controlFunctions'];
/* Projector image */
$projImage = $_POST['projImage'];
/* Screen Notes */
$screenNotes = $_POST['screenNotes'];
/* Control Notes */
$controlNotes = $_POST['controlNotes'];
/* Monitor power */
$monitorPower = $_POST['monitorPower'];
/* Network connection */
$networkConnect = $_POST['networkConnect'];
/* PC Power */
$pcPower = $_POST['pcPower'];
/* PC image */
$pcImage = $_POST['pcImage'];
/* PC audio */
$pcAudio = $_POST['pcAudio'];
/* PC DVD playback */
$pcDvd = $_POST['pcDvd'];
/* BluRay Player power */
$BluRayPower = $_POST['BluRayPower'];
/* Laptop VGA connection */
$laptopVga = $_POST['laptopVga'];
/* Visualiser Power */
$visPower = $_POST['visPower'];
/* bluRay Play back */
$BluRayPlay = $_POST['BluRayPlay'];
/* Laptop audio */
$laptopAudio = $_POST['laptopAudio'];
/* Visualiaser lamp */
$visLamp = $_POST['visLamp'];
/* BluRay Audio */
$BluRayAudio = $_POST['BluRayAudio'];
/* laptop HDMI */
$laptopHdmi = $_POST['laptopHdmi'];
/* Visualiser image */
$visImage = $_POST['visImage'];
/* Laptop Network Connection */
$laptopNetwork = $_POST['laptopNetwork'];
/* Visualiser automatic and manual zoom */
$visZoom = $_POST['visZoom'];
/* Lectern mic working */
$micLec = $_POST['micLec'];
/* Video conference power */
$vcPower = $_POST['vcPower'];
/* Condition of lectern Condition */
$lecternCondition = $_POST['lecternCondition'];
/* Radio mics working */
$audioRadioMics = $_POST['audioRadioMics'];
/* VC unit dials and connects */
$vcConnect = $_POST['vcConnect'];
/* General condition of cables Good */
$cableCondition = $_POST['cableCondition'];
/* Visualiser audio */
$vcAudio = $_POST['vcAudio'];
/* Condition of wall connections */
$wall = $_POST['wall'];
/* Visualiser laptop connection */
$vcLaptop = $_POST['vcLaptop'];
/* White board condition */
$whiteB = $_POST['whiteB'];
/* Video conference notes */
$vcNotes = $_POST['vcNotes'];

$sql = "INSERT INTO avChecklist (techNam, building, roomNum, day, month, 
projPower, screenUpDown, controlPower, projLamp, rips, controlFunctions, 
projImage, screenNotes, controlNotes, monitorPower, networkConnect, 
pcPower, pcImage, pcAudio, pcDvd, BluRayPower, laptopVga, visPower, 
BluRayPlay, laptopAudio, visLamp, BluRayAudio, laptopHdmi, visImage, 
laptopNetwork, visZoom, micLec, vcPower, lecternCondition, 
audioRadioMics, vcConnect, cableCondition, vcAudio, wall, vcLaptop, 
whiteB, vcNotes) VALUES ('$techNam', '$building', '$roomNum', '$day', 
'$month', '$projPower', '$screenUpDown', '$controlPower', '$projLamp', 
'$rips', '$controlFunctions', '$projImage', '$screenNotes', 
'$controlNotes', '$monitorPower', '$networkConnect', '$pcPower', 
'$pcImage', '$pcAudio', '$pcDvd', '$BluRayPower', '$laptopVga', 
'$visPower', '$BluRayPlay', '$laptopAudio', '$visLamp', '$BluRayAudio', 
'$laptopHdmi', '$visImage', '$laptopNetwork', '$visZoom', '$micLec', 
'$vcPower', '$lecternCondition', '$audioRadioMics', '$vcConnect', 
'$cableCondition', '$vcAudio', '$wall', '$vcLaptop', '$whiteB', 
'$vcNotes')";

 if (!mysql_query($sql)) {
 die('Error: ' . mysql_error());
 }
echo 'Thanks '. $techNam .' your completed maintenance check for room '. 
$roomNum .'  has been added to the database.';
echo "<br /><br /><br />";
echo 'This page will redirect in 5 seconds';
mysql_close();
?>

表结构

Database a9404870_heAv
Table structure for table avChecklist
Field   Type    Null    Default
submitDate  timestamp   Yes CURRENT_TIMESTAMP
techNam varchar(255)    Yes NULL
building    varchar(255)    Yes NULL
roomNum varchar(255)    Yes NULL
day varchar(255)    Yes NULL
month   varchar(255)    Yes NULL
projPower   varchar(255)    Yes NULL
screenUpDown    varchar(255)    Yes NULL
controlPower    varchar(255)    Yes NULL
projLamp    varchar(255)    Yes NULL
rips    varchar(255)    Yes NULL
controlFunctions    varchar(255)    Yes NULL
projImage   varchar(255)    Yes NULL
screenNotes varchar(255)    Yes NULL
controlNotes    varchar(255)    Yes NULL
monitorPower    varchar(255)    Yes NULL
networkConnect  varchar(255)    Yes NULL
pcPower varchar(255)    Yes NULL
pcImage varchar(255)    Yes NULL
pcAudio varchar(255)    Yes NULL
pcDvd   varchar(255)    Yes NULL
BluRayPower varchar(255)    Yes NULL
laptopVga   varchar(255)    Yes NULL
visPower    varchar(255)    Yes NULL
BluRayPlay  varchar(255)    Yes NULL
laptopAudio varchar(255)    Yes NULL
visLamp varchar(255)    Yes NULL
BluRayAudio varchar(255)    Yes NULL
laptopHdmi  varchar(255)    Yes NULL
visImage    varchar(255)    Yes NULL
laptopNetwork   varchar(255)    Yes NULL
visZoom varchar(255)    Yes NULL
micLec  varchar(255)    Yes NULL
vcPower varchar(255)    Yes NULL
lecternCondition    varchar(255)    Yes NULL
audioRadioMics  varchar(255)    Yes NULL
vcConnect   varchar(255)    Yes NULL
cableCondition  varchar(255)    Yes NULL
vcAudio varchar(255)    Yes NULL
wall    varchar(255)    Yes NULL
vcLaptop    varchar(255)    Yes NULL
whiteB  varchar(255)    Yes NULL
vcNotes varchar(255)    Yes NULL

Answer 1

为了确保某些内容设置为 NULL，您必须执行以下操作:

isset($_POST['screenNotes'])? $screenNotes = $_POST['screenNotes'] : $screenNotes = NULL;

如果字段留空，则必须对要插入 NULL 的每个字段执行此操作。

我在这里所做的是使用三元条件 - 它只是一个缩短的if条件:

<if this is true> ? <do this> : <else do that>;

有关三元运算符的更多信息，请参阅 the docs .