PHP uses mysqli extension to connect to MySQL database
Oct 09, 2016 pm 01:06 PMThis article mainly introduces PHP to use the mysqli extension to connect to the MySQL database. Friends who need it can refer to it
1. Object-oriented usage
$db = new mysqli('localhost', 'root', '123456', 'dbname');
If the database is not specified when establishing the connection, select the database to use and switch to use Database
$db->select_db('dbname'); $query = "SELECT * FROM user WHERE uid=4"; $result = $db->query($query); $result_num = $result->num_rows; $row = $result->fetch_assoc(); //返回一个关联数组,可以通过$row['uid']的方式取得值 $row = $result->fetch_row(); //返回一个列举数组,可以通过$row[0]的方式取得值 $row = $result->fetch_array(); //返回一个混合数组,可以通过$row['uid']和$row[0]两种方式取得值 $row = $result->fetch_object(); //返回一个对象,可以通过$row->uid的方式取得值 $result->free(); //释放结果集 $db->close(); //关闭一个数据库连接,这不是必要的,因为脚本执行完毕时会自动关闭连接
When performing INSERT, UPDATE, and DELETE operations, use $db->affected_rows to view the number of affected rows
2. Process-oriented usage
$db = mysqli_connect('localhost', 'root', '123456', 'dbname');
If the database is not specified when establishing a connection, the database will be selected. Database, switch the database used
mysqli_select_db($db, 'dbname');
Query the database
$query = "SELECT * FROM user WHERE uid=4"; $result = mysqli_query($db, $query); $result_num = mysqli_num_rows($result);
Return one row of results
$row = mysqli_fetch_assoc($result); //返回一个关联数组,可以通过$row['uid']的方式取得值 $row = mysqli_fetch_row($result); //返回一个列举数组,可以通过$row[0]的方式取得值 $row = mysqli_fetch_array($result); //返回一个混合数组,可以通过$row['uid']和$row[0]两种方式取得值 $row = mysqli_fetch_object($result); //返回一个对象,可以通过$row->uid的方式取得值
Disconnect the database
mysqli_free_result($result); //释放结果集 mysqli_close($db); //关闭一个数据库连接,这不是必要的,因为脚本执行完毕时会自动关闭连接
When performing INSERT, UPDATE, DELETE operations, use mysqli_affected_rows() to view the number of affected rows

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