PHP simple connection operation to mysql database

After I finished working on the company’s front-end static pages a while ago, I briefly learned the basics of PHP. Today I thought about reviewing the way PHP connects to the database, and write an essay and save it for later

php connect database port and create new database

<span style="color: #000000">php
        </span><span style="color: #800080">$servername</span> = "localhost"<span style="color: #000000">;
        </span><span style="color: #800080">$username</span> = "root"<span style="color: #000000">;
        </span><span style="color: #008000">//</span><span style="color: #008000"> 创建连接</span>
        <span style="color: #800080">$conn</span> = <span style="color: #008080">mysqli_connect</span>(<span style="color: #800080">$servername</span>, <span style="color: #800080">$username</span><span style="color: #000000">);
        </span><span style="color: #008000">//</span><span style="color: #008000"> 检测连接</span>
        <span style="color: #0000ff">if</span> (!<span style="color: #800080">$conn</span><span style="color: #000000">) {

            </span><span style="color: #0000ff">die</span>("连接失败: " . <span style="color: #008080">mysqli_connect_error</span><span style="color: #000000">());
        }

        </span><span style="color: #008000">//</span><span style="color: #008000"> 创建数据库</span>
        <span style="color: #800080">$sql</span> = "CREATE DATABASE myDB"<span style="color: #000000">;
        </span><span style="color: #0000ff">if</span> (<span style="color: #008080">mysqli_query</span>(<span style="color: #800080">$conn</span>, <span style="color: #800080">$sql</span><span style="color: #000000">)) {
            </span><span style="color: #0000ff">echo</span> "数据库创建成功"<span style="color: #000000">;
        } </span><span style="color: #0000ff">else</span><span style="color: #000000"> {
            </span><span style="color: #008000">//</span><span style="color: #008000">数据库已经存在</span>
            <span style="color: #0000ff">echo</span> "Error creating database: " . <span style="color: #008080">mysqli_error</span>(<span style="color: #800080">$conn</span><span style="color: #000000">);
        }

        </span><span style="color: #008080">mysqli_close</span>(<span style="color: #800080">$conn</span><span style="color: #000000">);
        </span>?>

After the connection is successful, create a simple data table

<span style="color: #008000">//</span><span style="color: #008000"> 使用 sql 创建数据表</span>
        <span style="color: #800080">$sql</span> = "<span style="color: #000000">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
        )</span>"<span style="color: #000000">;

        </span><span style="color: #0000ff">if</span> (<span style="color: #800080">$conn</span>->query(<span style="color: #800080">$sql</span>) === <span style="color: #0000ff">TRUE</span><span style="color: #000000">) {
            </span><span style="color: #0000ff">echo</span> "Table MyGuests created successfully"<span style="color: #000000">;
        } </span><span style="color: #0000ff">else</span><span style="color: #000000"> {
            </span><span style="color: #0000ff">echo</span> "创建数据表错误: " . <span style="color: #800080">$conn</span>-><span style="color: #000000">error;
        }</span>

When connecting to the database, make sure the server port of the database is open, otherwise you cannot connect. 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