PHP and MYSQL database connection tutorial sharing

php and mysql database

Teaching objectives:

1. Understand the MySQL database and be proficient in using mysql (phpMyadmin)

2. PHP code Realize the connection and CURD operation to the MySQL database

Teaching content:

Detailed explanation:

1. PHP connection to the database

1. Connect to the MYSQL server

Use the mysql_connect() function to create a connection with the mysql server.

2. Select the database

Use the mysql_select_db() function to select the database on the mysql database server and create a connection with the database.

3. Execute sql statement

Use the mysql_query() function to execute sql statement in the selected database.

4. Close the result set

Mysql_free_result(); After the database operation is completed, the result set needs to be closed to release system resources.

5. Close the mysql server

Use mysql_close(); every time the mysql_connect() or mysql_query() function is used, system resources will be consumed. When a small number of users access the web site, the problem is not serious, but if the number of user connections exceeds a certain number, the system performance will decrease or even crash. In order to avoid this phenomenon, after completing the database operation, you should use the mysql_close() function to close the connection with the mysql server to save system resources.

Note: The connection to the database in PHP is a non-persistent connection, and the system will automatically recycle it. Generally, there is no need to set it to close. However, if the result set returned at one time is relatively large or the website has a large number of visits, it is best to use the mysql_close() function to release it manually.

2. Connect to the database code

1. Connect to the server and select the database

/**
*@authorMissGE
*@since2012-2-16
*@descToolclass
*HandletheMySQLdatabase
*/
$conn=mysql_connect("localhost","root","");
if($conn)
{
echo"数据库连接成功";
}
else
{
Die(数据库连接失败",mysql_error());//die()函数表示向用户输出引号中的内容，程序终止执行
}
$select=mysql_select_db("school",$conn);//选择数据库
/*mysql_query("SET
character_set_connection=utf-8,character_set_results=utf-8,character_set_Client=binary",$conn);*/
Mysql_query("setnamesutf-8");//设置数据库编码格式是utf-8
if($select)
echo"选择数据库成功";
else
echo"选择数据库失败";
?>

2. Add a piece of data

Example: Registered user

3. Example: User login successfully

4. Modify or delete a piece of data

login.php
include("db.php");
?>

Register/Login user

User name:

Password:

$uName="";
$pwd="";
if($_POST["sub"])
{
$uName=$_POST["userName"];
$pwd=$_POST["pwd"];
$sql="insertinto`users`(`uName`,`uPwd`)values('".$uName."','".$pwd."')";
$query=mysql_query($sql,$conn);
if($query)
echo"注册成功";
else
echo"注册失败";
}
if($_POST["sub_1"])
{
$uName=$_POST["userName"];
$pwd=$_POST["pwd"];
echo$pwd;
$sql="select*fromuserswhereuName='".$uName."'anduPwd='".$pwd."'";
$query=mysql_query($sql,$conn);
$row=mysql_fetch_array($query);
if($row)
echo"";else
echo"登录失败";
}
?>
Db.php
$host="localhost";
$root="root";
$rPwd="";$conn=mysql_connect($host,$root,$rPwd);
if(!$conn)
die("连接数据库服务器失败".mysql_error());$select=mysql_select_db("school",$conn);mysql_query("setnamesgb2312");
if(!$select)
echo"选择数据库失败";
?>
Index_ok.php
echo"相信您的技术，您已登陆成功";echo"返回";?>

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