[英]Inserting/updating data into MySql database using php
I am trying to insert/update the MySql database depending on whether a post already exists on the database (I am checking this with a unique user_id). 我正在尝试插入/更新MySql数据库,具体取决于数据库中是否已存在帖子(我正在使用唯一的user_id进行检查)。 The following works:
以下作品:
$select_query = "SELECT * ";
$select_query .= "FROM test ";
$select_query .= "WHERE user_id = '$user_id'";
$check_user_id = mysqli_query($connection, $select_query);
$query = "INSERT INTO test (";
$query .= " user_id, name, message";
$query .= ") VALUES (";
$query .= " '{$user_id}', '{$name}', '{$message}'";
$query .= ")";
$result = mysqli_query($connection, $query);
if ($result) {
echo "Success!";
} else {
die("Database query failed. " . mysqli_error($connection));
}
However, when I use the following code with an if/else statement, it does not work anymore, although the console reports "Success!" 但是,当我将以下代码与if / else语句一起使用时,它不再起作用,尽管控制台报告“成功!” (meaning $result has a value).
(意思是$ result有一个值)。 Any help would be greatly appreciated.
任何帮助将不胜感激。 Thanks.
谢谢。
$select_query = "SELECT * ";
$select_query .= "FROM test ";
$select_query .= "WHERE user_id = '$user_id'";
$check_user_id = mysqli_query($connection, $select_query);
if (!$check_user_id) {
$query = "INSERT INTO test (";
$query .= " user_id, name, message";
$query .= ") VALUES (";
$query .= " '{$user_id}', '{$name}', '{$message}'";
$query .= ")";
} else {
$query = "UPDATE test SET ";
$query .= "name = '{$name}', ";
$query .= "message = '{$message}' ";
$query .= "WHERE user_id = '{$user_id}'";
}
$result = mysqli_query($connection, $query);
if ($result) {
echo "Success!";
} else {
die("Database query failed. " . mysqli_error($connection));
}
As i understand your code. 据我了解你的代码。 you are trying to check if the user_id is existing in your database.. i made a simple code and i think its works for me..
你试图检查你的数据库中是否存在user_id ..我做了一个简单的代码,我觉得它对我有用..
$select_query = mysql_query("SELECT * FROM test WHERE user_id = '$user_id'") or die (mysql_error());
$result = mysql_num_rows($select_query);
if(!$result){
$query = mysql_query("INSERT INTO test (user_id, name, message) VALUES ('$user_id', '$name', '$message')");
if($query){
echo "Success!";
}
else
{
die (mysql_error());
}
}
else{
$query2 = mysql_query("UPDATE test SET name='$name', message='$message' WHERE user_id = '$user_id'")
}
mysql_query
returns the operation identifier, not the actual result. mysql_query
返回操作标识符,而不是实际结果。 This is why $check_user_id
is always true, so you are always trying to update (even not existing!) rows. 这就是
$check_user_id
始终为true的原因,因此您总是尝试更新(甚至不存在!)行。
you have to "read" the result of mysql_query
by for example using 你必须通过例如使用来“读取”
mysql_query
的结果
$check_user_id = mysql_num_rows( mysql_query($connection, $select_query) );
now it returns 0 (false) iff there were no results for q $select_query
现在它返回0(false)iff没有q
$select_query
结果
This statement is giving you a resource to the result 此语句为您提供结果的资源
$check_user_id = mysqli_query($connection, $select_query);
next you are checking for if(!$check_user_id)
: this condition evaluates to false because of the negation !
接下来你要检查
if(!$check_user_id)
:由于否定,这个条件评估为false !
. 。 Thus your condition goes to the
else
part and and never enters the if
. 因此,您的条件将转到
else
部分,并且永远不会进入if
。
The $result
always has value because you are calling it towards the end of the script. $result
始终具有值,因为您在脚本末尾调用它。
Since you previously know the user_id, and assuming that is a primary key in the table, you could use "ON DUPLICATE KEY UPDATE" clause: 由于您以前知道user_id,并假设它是表中的主键,因此您可以使用“ON DUPLICATE KEY UPDATE”子句:
$query = mysql_query("INSERT INTO test (user_id, name, message)
VALUES ('$user_id', '$name', '$message')
ON DUPLICATE KEY
UPDATE name='$name', message='$message';
");
Same result with only one query. 只有一个查询的结果相同。
Ref: http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html 参考: http : //dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html
Use Code for data inserting in mysql. 使用代码在mysql中插入数据。
$query = mysql_query("INSERT INTO test set user_id = '$user_id', name = '$name', message = '$message'");
if($query){
echo "Success!";
}
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