Question

我正在尝试使用PDO将变量的值保存到数据库中，但是我收到Undefined variable错误。

奇怪的是，我可以在同一代码块中成功回显该变量，但仍然是错误表明该变量未在下一行定义（在echo语句之后）！

以下是代码：

<?php
    $sql = "SELECT po_number FROM po ORDER BY po_number DESC LIMIT 1 ;";
    $STH = $pdo ->query($sql);
    $row = $STH->fetch();
    $myVar = $row['po_number'];
?>

<?php
    if(isset($_POST['addProduct'])){
        echo $myVar;  //the variable can be echoed with the expected value here

        $sql1 = "INSERT INTO po_parts (po_number, part_id, quantity) VALUES (?,?,?)";
        $statement1->bindParam(1, $myVar);
        //I am getting error that $myVar is undefined on the previous line

        $statement1->bindParam(2, $_POST['part']);
        $statement1->bindParam(3, $_POST['quantity']);
        if($statement1->execute()){
            $message = "Product was added successfully to the order number $newVar";
        }else{
            $message = "OP's was NOT added successfully.";
        }
    }
?>

有谁能告诉我这里有什么问题？

谢谢。

Answer 1

您必须先准备好您的陈述，然后再使用它。

<?php
    $sql = "SELECT po_number FROM po ORDER BY po_number DESC LIMIT 1 ;";
    $STH = $pdo ->query($sql);
    $row = $STH->fetch();
    $myVar = $row['po_number'];
?>

<?php
    if(isset($_POST['addProduct'])){
        echo $myVar;  //the variable can be echoed with the expected value here

        $sql1 = "INSERT INTO po_parts (po_number, part_id, quantity) VALUES (?,?,?)";

        // Inserted this row
        $statement1 = $pdo->prepare($sql1);

        $statement1->bindParam(1, $myVar);
        //I am getting error that $myVar is undefined on the previous line

        $statement1->bindParam(2, $_POST['part']);
        $statement1->bindParam(3, $_POST['quantity']);
        if($statement1->execute()){
            $message = "Product was added successfully to the order number $newVar";
        }else{
            $message = "OP's was NOT added successfully.";
        }
    }
?>

Answer 2

在插入之前，您需要准备语句：

$statement1 = $pdo->prepare($sql1);

有关http://www.w3schools.com/php/php_mysql_prepared_statements.asp的MySQLi PDO语法的更多信息。

可以回显变量，但在尝试将其与PDO一起使用时，PHP会返回未定义的错误

2 个答案: