Question

我开始从Head First学习PHP和MySql，现在我在第2章学习，并且我正在从书中做一些练习。

    $connection = mysql_connect("127.0.0.1", "root", "", "aliendatabase")
or die ("Oops! Couldn't connect to server because ". mysql_error());



    $sql="INSERT INTO aliens_abduction (first_name, last_name, when_it_happened, how_long, how_many, alien_description, what_they_did, fang_spotted, other, email)
    VALUES ('$first_name', '$last_name', '$when_it_happened', '$how_long', 'how_many', '$alien_description', '$what_they_did', '$fang_spotted', '$other', '$email')";


    mysqli_query($connection, $sql)
    or die('Error querying database.' . mysql_error());

  mysqli_close($connection);

当我写这个部分的时候，我一直在＆＃34;错误查询数据库＆＃34;错误。任何人都可以告诉我这段代码中有什么问题吗？

Answer 1

从mysql_query开始后，你无法使用mysqli_query。

<?php

$connection = mysql_connect("127.0.0.1", "root", "", "test") or die ("Oops! Couldn't connect to server because ". mysql_error());
mysql_select_db("test");


$sql="INSERT INTO users (id) VALUES (100000)";


mysql_query($sql,$connection) or die('Error querying database.' . mysql_error());

mysql_close($connection);

以下是 Mysqli 的教程：Link

为此目的，这里是mysqli代码：

$db = new mysqli('localhost', 'root', '', 'aliendatabase');

if($db->connect_errno > 0){
    die('Unable to connect to database [' . $db->connect_error . ']');
}

$sql = "INSERT INTO aliens_abduction (first_name, last_name, when_it_happened, how_long, how_many, alien_description, what_they_did, fang_spotted, other, email)
VALUES ('$first_name', '$last_name', '$when_it_happened', '$how_long', 'how_many', '$alien_description', '$what_they_did', '$fang_spotted', '$other', '$email')";

if(!$result = $db->query($sql)){
    die('There was an error running the query [' . $db->error . ']');
}

$db->close();

Answer 2

你正在混合mysqli（注意（i））和mysql（注意（i）的缺失）。这两个库不可互换/混合。在一个中建立的连接不能被另一个使用。

请注意您的来电差异：

mysql_connect()
mysqli_query()
mysql_error()
mysqli_close()

Answer 3

为此目的，这里是mysqli代码：

$db = new mysqli('localhost', 'root', '', 'aliendatabase');

if($db->connect_errno > 0){
    die('Unable to connect to database [' . $db->connect_error . ']');
}

$sql = "INSERT INTO aliens_abduction (first_name, last_name, when_it_happened, how_long, how_many, alien_description, what_they_did, fang_spotted, other, email)
VALUES ('$first_name', '$last_name', '$when_it_happened', '$how_long', 'how_many', '$alien_description', '$what_they_did', '$fang_spotted', '$other', '$email')";

if(!$result = $db->query($sql)){
    die('There was an error running the query [' . $db->error . ']');
}

$db->close();

Answer 4

你不应该使用mysql。原因在本文中解释。 http://php.net/manual/en/migration55.deprecated.php 此外，您不能将mysqli与mysql混合使用。这是一个简短的解决方案unsing mysqli

$connection = new mysqli("127.0.0.1", "root", "", "test") 


$sql="INSERT INTO users (id) VALUES (100000)";


if(mysqli_query($sql,$connection))
{
   //message  if everything goes right
}
else
{
   printf("Error: %s\n", mysqli_error($connection)); //will print the errors
}

查询数据库时出错

4 个答案: