Let's talk about the general steps for PHP to access Mysql database

With the development of the Internet, the number and types of websites are increasing, and most of them need to interact with databases to store and operate data. Among many databases, the Mysql database has become the first choice for the majority of website developers because of its open source, reliability, and stability. As the most popular server-side programming language at present, PHP is often used in conjunction with Mysql database. This article will introduce the general steps for PHP to access the Mysql database.

1. Connect to Mysql database

First, we need to connect to Mysql database. The following is the basic syntax for connecting to the Mysql database:

$link = mysqli_connect('服务器地址','用户名','密码','数据库名称');

Among them, the $link variable is used to store the connection handle, 'server address' refers to the server where the Mysql database is located Address, 'username' and 'password' are the login information for the Mysql database, 'database name' is the name of the database that needs to be connected. It should be noted that when connecting to the Mysql database, you need to ensure that the user name and password used have sufficient permissions to access the corresponding database.

2. Execute the query statement

After the connection is successful, we can execute the query statement. Unlike other programming languages, PHP provides multiple methods to execute query statements. The following are two basic methods:

1. mysqli_query() function

mysqli_query()The function is used to execute any type of query statement, including SELECT, INSERT, UPDATE and DELETE. The following is an example of using the mysqli_query() function to execute a SELECT query statement:

$sql = "SELECT * FROM `table_name`";
$result = mysqli_query($link, $sql);

//获取查询结果
while($row = mysqli_fetch_assoc($result)) {
    //处理查询结果
}

Among them, the $sql variable stores the SELECT query statement to be executed, The $result variable stores the execution result. mysqli_fetch_assoc()The function is used to obtain query results row by row and store the query results in an associative array. By processing associative arrays, we can obtain each row of data from the query results.

2. mysqli_prepare() function and mysqli_stmt_bind_param() function

If we need to use parameterized query statements, we can use the mysqli_prepare() function and mysqli_stmt_bind_param()Function. The following is an example of using a parameterized query statement to obtain data that meets certain conditions:

$name = "John";
$age = 30;

//使用参数化查询语句
$stmt = mysqli_prepare($link, "SELECT * FROM `table_name` WHERE `name`=? AND `age`=?");
mysqli_stmt_bind_param($stmt, "si", $name, $age);
mysqli_stmt_execute($stmt);

//获取查询结果
$result = mysqli_stmt_get_result($stmt);
while($row = mysqli_fetch_assoc($result)) {
    //处理查询结果
}

Among them, the $name and $age variables are the query conditions. The mysqli_prepare() function is used to prepare parameterized query statements, and the mysqli_stmt_bind_param() function is used to bind query conditions. Supports multiple binding methods, where "s" represents a string and i represents an integer. Use the mysqli_stmt_execute() function to execute the query, and the mysqli_stmt_get_result() function is used to obtain the query results.

3. Close the database connection

After we have performed all operations that require the use of the database, we need to close the database connection. The following is the basic syntax for closing a database connection:

mysqli_close($link);

Among them, the $link variable is the connection handle we obtain when connecting to the Mysql database.

Summary

This article introduces the general steps for PHP to access the Mysql database, including connecting to the Mysql database, executing query statements and closing the database connection. For most websites, interacting with the database is a very important part. Understanding the cooperation between Mysql database and PHP can help us store and operate data more efficiently, thereby achieving a good user experience and effect.

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