Question

我有一个问题，我试图做可以执行sql语法的函数，但是当我试图执行它时mysqli_querry丢弃一个错误，导致这个函数需要两个参数。但我有另一个连接到数据库的功能，我该如何解决这个问题呢？

function connect_to_database($servername, $username,$password,$dbname) {
    $conn = new mysqli($servername, $username, $password, $dbname);
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
}

function execute($get_sql) {
    $sql[0] = $get_sql;
    mysqli_query($sql[0]);
}

connect_to_database("localhost","root","root","m1_14");
execute("INSERT INTO teszt_1 (email,username,order,createdate) VALUES ('test@gmail.com','test','test',NOW())");

Answer 1

您需要声明变量“global”：

<?php
    $conn = null; // ◄■■■
    $result = null; // ◄■■■

    function connect_to_database($servername, $username,$password,$dbname)
    { global $conn; // ◄■■■
        $conn = new mysqli($servername, $username, $password, $dbname);
        if ($conn->connect_error)
        {
            die("Connection failed: " . $conn->connect_error);
        }
    }

    function execute($get_sql)
    { global $conn; // ◄■■■
      global $result; // ◄■■■
        $sql[0] = $get_sql;
        $result = mysqli_query($conn,$sql[0]); // ◄■■■ $CONN AND $RESULT.
    }

    connect_to_database("localhost","root","root","m1_14");
     execute("INSERT INTO teszt_1 (email,username,order,createdate) " .
             "VALUES ('test@gmail.com','test','test',NOW())");

    execute("select * from teszt_1");

    foreach ( $result as $row ) // ◄■■■ USE $RESULT HERE.
      echo $row["email"];

全局变量允许您将值从一个函数传递到另一个函数。

如果是“插入”，则您不需要$result，如果是“选择”，您可以使用$result来访问这些值。

Answer 2

这样做：

mysqli_query需要两个参数而且只提供一次，所以为execute函数提供mysqli_query函数的所有参数

function connect_to_database($servername, $username,$password,$dbname) {
    $conn = new mysqli($servername, $username, $password, $dbname);
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
    //return connection or define connection as global and use as global scenario
    return $conn;
}

function execute($get_sql, $connect) {
    $sql[0] = $get_sql;
    mysqli_query($connect, $sql[0]);
}

$connection = connect_to_database("localhost","root","root","m1_14");
execute("INSERT INTO teszt_1 (email,username,order,createdate) VALUES ('test@gmail.com','test','test',NOW())", $connection);

连接数据库后执行功能

2 个答案: