php MySQL

全是面向过程的

连接connect

MySQLi 面向过程

使用mysqli_connect($servername, $username, $password)

通过mysqli_connect_error()报错

使用mysqli_close()关闭连接

$servername="localhost";
$username="root";
$password="654321";

$con=mysqli_connect($servername,$username,$password);

if(!$con)
    die('Unable to connect:'.mysqli_connect_error());

echo "连接成功";

创建MySQL数据库

使用mysqli_query($connect,$sql)创建数据库

//创建数据库
$sql="create database myDB";
if(mysqli_query($con,$sql)){
    echo "Insert successfully!";
}else{
    echo "Unable to insert!".mysqli_error($con);
}
mysqli_close($con);

创建表

mysqli_query() 函数执行某个针对数据库的查询。

//连接数据库要改成以下
$servername="localhost";
$username="root";
$password="654321";
$dbname="myDB";

$con=mysqli_connect($servername,$username,$password,$dbname);

//创建表
$sql2="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(mysqli_query($con,$sql2)){
    echo "插入表成功";
}else{
    echo "插入失败 : ".mysqli_error($con);
}

插入数据

//插入数据
//Student(Sno,Sname,Sage,Ssex)学生表
$sql="insert into student values (1,'网购用',21,'男');";
if(mysqli_query($con,$sql)){
    echo "插入成功";
}else{
    echo "插入失败".mysqli_error($con);
}

插入多条数据

使用mysqli_multi_query()函数执行多条SQL语句

//插入多条数据
$sql="insert into student values (2,'狗吠',21,'男');";
$sql="insert into student values (3,'张海',19,'男');";

if(mysqli_multi_query($con,$sql)){
    echo "插入成功";
}else{
    echo "插入失败";
}

读取数据

先写好查询语句 , 然后将结果赋值给变量$result

通过函数mysqli_num_rows()判断返回的数据

如果是多条数据 , 通过函数fetch_assoc()将结果放到关联数组中并循环输出

$sql="select * from student";
$result=mysqli_query($con,$sql);
//Student(Sno,Sname,Sage,Ssex)学生表
if(mysqli_num_rows($result)>0){
    while($row=mysqli_fetch_assoc($result)){
        echo "Sno : ".$row['Sno']." , Sname : ".$row['Sname']." , Sage : ".$row['Sage']." , Ssex : ".$row['Ssex'];
        echo "<br>";
    }
}else{
    echo "没有结果";
}