处理重复条目的错误 - PHP MySQL
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Handle error for duplicate entries - PHP MySQL
提问by RobHardgood
I have a PHP form which enters data into my MySQL database. My primary key is one of the user-entered values. When the user enters a value that already exists in the table, the MySQL error "Duplicate entry 'entered value' for key 1" is returned. Instead of that error, I would like to alert the user that they need to enter a different value. Just an echoed message or something. I guess my question comes down to: how to turn a specific MySQL error into a PHP message Thanks
我有一个 PHP 表单，可以将数据输入到我的 MySQL 数据库中。我的主键是用户输入的值之一。当用户输入表中已存在的值时，返回 MySQL 错误“Duplicate entry 'entered value' for key 1”。而不是那个错误，我想提醒用户他们需要输入不同的值。只是一个回显的消息或其他东西。我想我的问题归结为：如何将特定的 MySQL 错误转换为 PHP 消息 谢谢
edit: nickf's answer below is nice, but is there any way to discern between specific errors?
编辑：nickf 在下面的回答很好，但是有什么方法可以区分特定错误吗？
回答by jensgram
To check for this specific error, you need to find the error code. It is 1062for duplicate key. Then use the result from errno()to compare with:
要检查此特定错误，您需要找到错误代码。它1062用于重复密钥。然后使用结果与以下内容errno()进行比较：
mysqli_query('INSERT INTO ...');
if (mysqli_errno() == 1062) {
print 'no way!';
}
A note on programming style
You should always seek to avoid the use of magic numbers(I know, I was the one to introduce it in this answer). Instead, you could assign the known error code (1062) to a constant (e.g. MYSQLI_CODE_DUPLICATE_KEY). This will make your code easier to maintain as the condition in the ifstatement is still readable in a few months when the meaning of 1062has faded from memory :)
关于编程风格的说明
您应该始终避免使用幻数（我知道，我是在这个答案中介绍它的人）。相反，您可以将已知错误代码 ( 1062)分配给一个常量 (例如MYSQLI_CODE_DUPLICATE_KEY)。这将使您的代码更易于维护，因为if语句中的条件在几个月后仍然可读，而 的含义1062已从记忆中消失:)
回答by nickf
You can check the return value from mysql_querywhen you do the insert.
您可以检查mysql_query插入时的返回值。
$result = mysql_query("INSERT INTO mytable VALUES ('dupe')");
if (!$result) {
echo "Enter a different value";
} else {
echo "Save successful.";
}
回答by Hassan Saeed
try this code to handle duplicate entries and show echo message:
尝试使用此代码处理重复条目并显示回显消息：
$query = "INSERT INTO ".$table_name." ".$insertdata;
if(mysqli_query($conn,$query)){
echo "data inserted into DB<br>";
}else{
if(mysqli_errno($conn) == 1062)
echo "duplicate entry no need to insert into DB<br>";
else
echo "db insertion error:".$query."<br>";
}//else end
回答by Codler
With mysql_error()function http://php.net/manual/en/function.mysql-error.php
使用mysql_error()函数 http://php.net/manual/en/function.mysql-error.php
回答by Chad timothy
Use mysql_errno()function, it returns the error numbers. The error number for duplicate keys is 1062.
for example
使用mysql_errno()函数，它返回错误号。重复键的错误号是 1062。例如
$query = mysql_query("INSERT INTO table_name SET ...);
if (mysql_errno() == 1062){
echo 'Duplicate key';
}
