PHP simple connection operation to mysql database

After finishing the company's front-end static page a while ago, I briefly learned the basic knowledge of PHP. Today I thought about reviewing the way PHP connects to the database, write an essay and save it for a look

php connects to the database port and Create a new database

<?php
        $servername = "localhost";
        $username = "root";
        // 创建连接
        $conn = mysqli_connect($servername, $username);
        // 检测连接
        if (!$conn) {

            die("连接失败: " . mysqli_connect_error());
        }

        // 创建数据库
        $sql = "CREATE DATABASE myDB";
        if (mysqli_query($conn, $sql)) {
            echo "数据库创建成功";
        } else {
            //数据库已经存在
            echo "Error creating database: " . mysqli_error($conn);
        }

        mysqli_close($conn);
        ?>

After the connection is successful, create a simple data table

// 使用 sql 创建数据表
        $sql = "CREATE TABLE MyGuests (
        id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
        firstname VARCHAR(30) NOT NULL,
        lastname VARCHAR(30) NOT NULL,
        email VARCHAR(50),
        reg_date TIMESTAMP
        )";

        if ($conn->query($sql) === TRUE) {
            echo "Table MyGuests created successfully";
        } else {
            echo "创建数据表错误: " . $conn->error;
        }

When connecting to the database, make sure that the server port of the database is open, otherwise it cannot be connected. Before writing the code, you can use navicat to test the connection to the database.

When learning, open the database service, which can be done through the integrated environment of wamp