我想通过下面的表单更新MySQL行。表单效果很好但是,如果我将字段留空,它会将MySQL中的字段更改为空白。我想更新sql但跳过任何空白的字段。
我已经阅读了几种方法,但它们似乎不符合逻辑。即在sql字符串本身中使用if语句。 (让MySQL完成应该在PHP中完成的工作)。
if($_SERVER['REQUEST_METHOD'] != 'POST')
{
echo '<form method="post" action="">
ID: <input type="text" name="a" /><br>
Program: <input type="text" name="b" /><br>
Description: <textarea row="6" cols="50" name="c"></textarea><br>
Cost: <input type="text" name="d"><br>
<input type="submit" value="Add Link" />
</form>';
}
try {
$dbh = new PDO($dsn, $user, $pass);
$dbh->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$stmt = $dbh->prepare('UPDATE links SET Program = :program , Descr = :descr, Cost = :cost WHERE Id= :id');
$stmt->bindParam(":id", $_POST["a"]);
$stmt->bindParam(":program", $_POST["b"]);
$stmt->bindParam(":descr", $_POST["c"]);
$stmt->bindParam(":cost", $_POST["d"]);
$stmt->execute();
if (!$stmt) {
echo "\nPDO::errorInfo():\n";
print_r($dbh->errorInfo());}
$dbh = null;
}
}catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
答案 0 :(得分:4)
这样的事情应该有效
.
.
.
$q = array();
if(trim($_POST["b"]) !== ""){
$q[] = "Program = :program";
}
if(trim($_POST["c"]) !== ""){
$q[] = "Descr = :descr";
}
if(trim($_POST["d"]) !== ""){
$q[] = "Cost = :cost";
}
if(sizeof($q) > 0){//check if we have any updates otherwise don't execute
$query = "UPDATE links SET " . implode(", ", $q) . " WHERE Id= :id";
$stmt = $dbh->prepare($query);
$stmt->bindParam(":id", $_POST["a"]);
if(trim($_POST["b"]) !== ""){
$stmt->bindParam(":program", $_POST["b"]);
}
if(trim($_POST["c"]) !== ""){
$stmt->bindParam(":descr", $_POST["c"]);
}
if(trim($_POST["d"]) !== ""){
$stmt->bindParam(":cost", $_POST["d"]);
}
$stmt->execute();
}
.
.
.
答案 1 :(得分:1)
更改声明:
$stmt = $dbh->prepare('UPDATE links SET Program = :program , Descr = :descr, Cost = :cost WHERE Id= :id');
如下:
$stmt = $dbh->prepare('UPDATE links SET Program = IF(trim(:program)="", Program, :program) , Descr = IF(trim(:descr)="", Descr, :descr), Cost = IF(trim(:cost)="", Cost, :cost) WHERE Id= :id');
答案 2 :(得分:0)
检查帖子字段为空: 如果任何字段数据为空,它将跳过更新查询。
If( $_POST["a"] && $_POST["b"] && $_POST["c"] && $_POST["d"]){
try {
$dbh = new PDO($dsn, $user, $pass);
$dbh->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$stmt = $dbh->prepare('UPDATE links SET Program = :program , Descr = :descr, Cost = :cost WHERE Id= :id');
$stmt->bindParam(":id", $_POST["a"]);
$stmt->bindParam(":program", $_POST["b"]);
$stmt->bindParam(":descr", $_POST["c"]);
$stmt->bindParam(":cost", $_POST["d"]);
$stmt->execute();
if (!$stmt) {
echo "\nPDO::errorInfo():\n";
print_r($dbh->errorInfo());}
$dbh = null;
}
}catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
}
Option2更新除空之外的所有字段:
try {
$sql ="UPDATE links SET ";
if($_POST["a"])
$sql .=" Program = :program ,";
if($_POST["b"])
$sql .=" Descr = :descr ,";
if($_POST["c"])
$sql .=" Cost = :cost ,";
$sql = rtrim($sql,',');
$dbh = new PDO($dsn, $user, $pass);
$dbh->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$stmt = $dbh->prepare($sql);
if($_POST["a"])
$stmt->bindParam(":id", $_POST["a"]);
if($_POST["b"])
$stmt->bindParam(":program", $_POST["b"]);
if($_POST["c"])
$stmt->bindParam(":descr", $_POST["c"]);
$stmt->execute();
if (!$stmt) {
echo "\nPDO::errorInfo():\n";
print_r($dbh->errorInfo());}
$dbh = null;
}
catch (PDOException $e) {
print "Error!: " . $e->getMessage() . "<br/>";
die();
}
答案 3 :(得分:0)
在PDO中使用未命名参数进行动态查询并将其作为数组传递到execute()
更容易。除非至少有1个参数与id一起传递,否则不会执行该语句。我已经离开了派生语句的回声和数组的转储。
示例陈述
UPDATE `links` SET `Program` = ? , `Cost` = ? WHERE `Id` = ?
示例数组
Array ( [0] => 2 [1] => 3 [2] => 2 )
if(isset($_GET['a'])){
$id = $_GET['a'];
$program = isset($_GET['b']) ? $_GET['b'] : NULL;
$descr = isset($_GET['c']) ? $_GET['c'] : NULL;
$cost= isset($_GET['d']) ? $_GET['d'] : NULL;
$params =array();
$sql = "UPDATE `links` SET "; //SQL Stub
if (isset($program)) {
$sql .= " `Program` = ? ,";
array_push($params,$program);
}
if (isset($descr)) {
$sql .= " `Descr` = ? ,";
array_push($params,$descr);
}
if (isset($cost)) {
$sql .= " `Cost` = ? ,";
array_push($params,$cost);
}
$sql = substr($sql, 0, -1);//Remove trailing comma
if(count($params)> 0){//Only execute if 1 or more parameters passed.
$sql .= " WHERE `Id` = ? ";
array_push($params,$id);
echo $sql;//Test
print_r($params);//Test
$stmt = $dbh->prepare($sql);
$stmt->execute($params);
}
}