PHP connects to the database and implements the addition, deletion, modification and query functions of the database

mySQLi database connection: (only applicable to PHP5 and above, please use mySQL to connect after PHP5)

1. Process-oriented method

//连接数据库，参数分别为本地（localhost），用户名（默认是root），密码（默认是空），数据库名（你要连接的数据库名称）。 $link = mysqli_connect('localhost','root','','mydb'); if(mysqli_errno($link)){ //检测数据库是否连接成功，如果连接失败输出错误，否则数据库连接成功 echo mysqli_error($link); }else{ echo '连接数据库成功'; }

2. Object-oriented method

$mysqli = new mysqli('localhost','root','','mydb'); if($mysqli->errno){ echo $mysqli->error; }else{ echo'连接数据库成功'; }

Add, delete, modify and query the database through the constructor:

1. Add data to the database

function add($sql){ $mysqli = new mysqli('localhost','root','','mydb'); mysqli_set_charset($mysqli,'utf8'); //设置编码格式 让数据库支持中文 if($mysqli->errno){ echo $mysqli->error; }else{ echo '连接数据库成功'; } $res = $mysqli->query($sql); if($res){ return true; }else{ return false; } }

Example usage: Add data to the table indicated as users

$name = "马云"; $age = 38; $pwd = 123789; $sql = "INSERT INTO users (username,age,pwd) VALUES ('$name',$age,$pwd)"; $res = add($sql); if($res){ //检测是否添加成功 echo '添加成功'; }else{ echo '添加失败'; }

2. Update database:

function update($sql){ $link =mysqli_connect('localhost','root','','mydb'); mysqli_set_charset($link,'utf8'); if(mysqli_errno($link)){ echo mysqli_error($link); }else{ echo'连接数据库成功'; }; $res =mysqli_query($link,$sql); if($res){ return true; }else{ return false; } }

Example usage: add data to the table named users

$sql = "UPDATE users SET username='王健林' WHERE id=23"; $res = update（$sql）; if($res){ echo'更新成功'; }else{ echo'更新失败'; }

3. Delete (use update instead of delete)

function delete($sql){ $link =mysqli_connect('localhost','root','','mydb'); mysqli_set_charset($link,'utf8'); if(mysqli_errno($link)){ echo mysqli_error($link); }else{ echo'连接数据库成功'; }; $res =mysqli_query($link,$sql); if($res){ return true; }else{ return false; } }

Example usage:

$sql ="DELETE FROM users WHERE id=23"; $res = delete($sql); if($res){ echo'删除成功'; }else{ echo'删除失败'; }

Query:

function getlist($sql){ $link =mysqli_connect('localhost','root','','mydb'); mysqli_set_charset($link,'utf8'); if(mysqli_errno($link)){ echo mysqli_error($link); }else{ echo'连接数据库成功'; }; $res =mysqli_query($link,$sql); // 返回查询到的所有数据 // $list = mysqli_fetch_all($res); //常用 while($list =mysqli_fetch_assoc($res)){ $arr[] = $list; } return $arr; }

Example usage:

$sql ="SELECT * FROM users"; $res = getlist($sql); print_r($res);