在带有存储过程的 php 中使用 pdo
我在 MySQL 数据库中有一个简单的存储过程:
I have a simple stored procedure in MySQL database:
DELIMITER $$
CREATE DEFINER=`vidhu`@`%` PROCEDURE `test`(var_datain TEXT)
BEGIN
SELECT var_datain;
END
在 mysql-workbench 中调用此过程时，它返回我输入的数据:
When calling this procedure in mysql-workbench it returns the data I put in:
现在，当我使用 pdo 从 PHP 调用它时，出现错误:
Now when I call it from PHP using pdo I get an error:
Fatal error: Cannot pass parameter 2 by reference in C:/apache......(3rd line)
这是我的php代码:
$db = new PDO(DSN, DBUSER, DBPASS);
$stmt = $db->prepare("CALL test(?)");
$stmt->bindParam(1, 'hai!', PDO::PARAM_STR);
$rs = $stmt->execute();
$result = $stmt->fetchAll(PDO::FETCH_ASSOC);
echo $result[0];
推荐答案
您需要使用 bindValue 而不是 bindParam.
You need to use bindValue instead of bindParam.
当你使用 bindParam 时，它绑定的是提供给参数的变量，而不是变量的值.
When you use bindParam, it binds the variable provided to the parameter, not the value of the variable.
所以，如果你这样做:
$x = 5;
$stmt->bindParam(1, $x, PDO::PARAM_INT);
$x = 6;
$stmt->execute(); //executes with 6 instead of 5
它实际上是用 6 而不是 5 来执行的.为此，该方法必须具有对变量的引用.你不能引用文字，所以这意味着 bindParam 不能与文字(或任何你不能引用的东西)一起使用.
It's actually executed with 6 rather than 5. To do this, the method must have a reference to the variable. You cannot have a reference to a literal, so this means that bindParam cannot be used with literals (or anything you can't have a reference to).
$x = 5;
$stmt->bindValue(1, $x, PDO::PARAM_INT);
$x = 6;
$stmt->execute(); //executes with 5 instead of 6
那么:
$stmt->bindParam(1, 1, PDO::PARAM_INT);
//invalid because there's no way to pass a literal 1 by reference
$stmt->bindValue(1, 1, PDO::PARAM_INT);
//valid
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