What does conn mean in php

conn represents database connection in PHP and is used to establish a connection with the database server. It can be used to perform database operations such as querying, inserting, updating, and deleting data. Get the conn variable through the mysqli_connect() or PDO() function, passing in the host name, user name, password and database name. This variable can be used to perform database operations later, and the connection needs to be closed at the end to avoid memory leaks.

The meaning of conn in PHP

conn is an abbreviation in PHP, which generally represents a database connection. It is typically used to store connection information established with a database server.

Purpose

The conn variable is used to perform database-related operations in PHP scripts, such as:

• Query data
• Insert or update data
• Delete data

Get the conn variable

To get the conn variable, you can use the built-in function in PHP Function mysqli_connect() or PDO(). These functions require the following parameters:

• Host name or IP address: Address of the database server
• User name: Used to connect to the database Username
• Password: Password to connect to the database
• Database name: Name of the database to connect to (## only #mysqli_connect())

Example

<code class="php">// 使用 mysqli_connect() 函数
$conn = mysqli_connect('localhost', 'username', 'password', 'database_name');

// 使用 PDO() 函数
$conn = new PDO('mysql:host=localhost;dbname=database_name', 'username', 'password');</code>

Next steps

Once you have the conn variable , you can use it to perform database operations. For example:

<code class="php">// 查询数据
$result = mysqli_query($conn, "SELECT * FROM users");

// 插入数据
mysqli_query($conn, "INSERT INTO users (name, email) VALUES ('John Doe', 'john.doe@example.com')");

// 更新数据
mysqli_query($conn, "UPDATE users SET name='Jane Doe' WHERE id=1");

// 删除数据
mysqli_query($conn, "DELETE FROM users WHERE id=1");</code>

In order to avoid memory leaks, the connection should be closed promptly after using the conn variable. This can be achieved by calling the

mysqli_close() or $conn->close() function.

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