为什么我不能运行两个 mysqli 查询?第二个失败

问题描述

是否可以像这样有两个 mysqli 查询?

Is it possible to have two mysqli queries like so?

mysqli_query($dblink, "INSERT INTO images (project_id, user_id, image_name, date_created, link_to_file, link_to_thumbnail, given_name) VALUES ('$project_id', '$user_id', '$image_name', '$date_created', '$link_to_file', '$thumbnail', '$ImageName')");
mysqli_query($dblink, "INSERT INTO images_history (project_id, user_id, image_name, date_created, link_to_file, link_to_thumbnail, given_name, day, month, year) VALUES ('$project_id', '$user_id', '$image_name', '$date_created', '$link_to_file', '$thumbnail', '$ImageName', '$day', '$month', '$year')");

基本上我想更新我的数据库中的两个表.有没有更好的方法来做到这一点?

Basically I want to update two tables in my DB. Is there a better way to do this?

推荐答案

mysqli_multi_query() 可以实现.

示例:

<?php

$mysqli = new mysqli($host, $user, $password, $database);

// create string of queries separated by ;
$query  = "INSERT INTO images (project_id, user_id, image_name, date_created, link_to_file, link_to_thumbnail, given_name) VALUES ('$project_id', '$user_id', '$image_name', '$date_created', '$link_to_file', '$thumbnail', '$ImageName');";
$query .= "INSERT INTO images_history (project_id, user_id, image_name, date_created, link_to_file, link_to_thumbnail, given_name, day, month, year) VALUES ('$project_id', '$user_id', '$image_name', '$date_created', '$link_to_file', '$thumbnail', '$ImageName', '$day', '$month', '$year');";

// execute query - $result is false if the first query failed
$result = mysqli_multi_query($mysqli, $query);

if ($result) {
    do {
        // grab the result of the next query
        if (($result = mysqli_store_result($mysqli)) === false && mysqli_error($mysqli) != '') {
            echo "Query failed: " . mysqli_error($mysqli);
        }
    } while (mysqli_more_results($mysqli) && mysqli_next_result($mysqli)); // while there are more results
} else {
    echo "First query failed..." . mysqli_error($mysqli);
}

关键是，如果您想在一次调用中执行多个查询，必须使用 mysqli_multi_query.出于安全原因，mysqli_query 不会执行多个查询以防止 SQL 注入.

The key is that you must use mysqli_multi_query if you want to execute more than one query in a single call. For security reasons, mysqli_query will not execute multiple queries to prevent SQL injections.

还要记住 mysqli_store_result 的行为.如果查询没有结果集(INSERT 查询没有)，它返回 FALSE 所以你还必须检查 mysqli_error 以查看它返回一个空字符串表示 INSERT 成功.

Also keep in mind the behavior of mysqli_store_result. It returns FALSE if the query has no result set (which INSERT queries do not) so you must also check mysqli_error to see that it returns an empty string meaning the INSERT was successful.

见:
mysqli_multi_query
mysqli_more_results
mysqli_next_result
mysqli_store_result

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