条件expression attribute_not_exists（）

发布于 2025-02-06 20:23:16 字数 746 浏览 0 评论 0原文

在数据库上插入项目时，我正在尝试使用条件表达，但是在PutItem（）函数运行时，PHP脚本不起作用。

如果他不存在，我想插入物品。

$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    ),
    'ConditionExpression' => 'attribute_not_exists(serialNumber)'
));

我试图将$响应var_dump var_dump上面的函数折断。

SerialNumber它的分区密钥，应该按预期工作。

下面的代码正常运行，但他用新值代替了现有项目，这是我不想发生的。

$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    )
));

原文

I am trying to use ConditionExpression when inserting an item on the database, but it dont work, the php script breaks when the Putitem() function runs.

I want to insert the item if he dont exist.

$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    ),
    'ConditionExpression' => 'attribute_not_exists(serialNumber)'
));

I tried to var_dump the $response but the code breaks on the function above.

serialNumber its a Partition Key which should work as intended.

The code below works fine, but he replaces the existing item with new values, which its what i dont want to happen.

$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    )
));

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温柔少女心 2025-02-13 20:23:16

预计您将返回condidtioncheckfailedexception当您设置为false的条件时。尝试将代码包装在尝试/捕获块中以查看它是否可以按预期工作？

try {
$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    )
));
}
catch(Exception $e) {
  echo $e->getMessage();
}

It is expected that you are returned a CondidtionCheckFailedException when the condition you set evaluates to false. Try wrapping your code in a try/catch block to see if it works as expected?

try {
$response = $client->putItem(array(
    'TableName' => 'tablename',
    'Item' => array(
        'serialNumber'   => array('S' => 'test123'),
        'deviceType' => array('S' => '1')
    )
));
}
catch(Exception $e) {
  echo $e->getMessage();
}

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