How to delete records from database table via PHP code

Deleting table records is a very common operation in PHP programming. This is because when developing web applications, you usually need to interact with a database to store and retrieve data. In this process, it is often necessary to delete records in the table. However, deletion should not be done lightly as it will result in permanent data loss. In this article, we will learn how to delete records from a database table through PHP code.

First, let us understand the concept of delete operation. A delete operation refers to deleting one or more records from a relational database. In PHP you can use different types of queries to perform delete operations. These queries include:

1. DELETE query statement: DELETE query is used to delete specified records in a single table. If you want to delete the entire table, you can use TRUNCATE query.
2. DROP query statement: DROP query is used to delete the entire table.

The following is a simple PHP code example to delete a record in the table:

<?php
//连接到数据库
$conn = mysqli_connect("localhost", "root", "password", "database_name");

//检查连接是否成功
if (!$conn) {
    die("Connection failed: " . mysqli_connect_error());
}

//设置要删除的记录ID
$id = 1;

//构建删除记录的SQL语句
$sql = "DELETE FROM table_name WHERE id=$id";

//执行删除记录操作
if (mysqli_query($conn, $sql)) {
    echo "Record deleted successfully";
} else {
    echo "Error deleting record: " . mysqli_error($conn);
}

//关闭数据库连接
mysqli_close($conn);
?>

The above code demonstrates how to use the DELETE query to delete a record in the table. In the code, we use the mysqli_connect() function to connect to the database and output error information through the mysqli_connect_error() function when it fails. Next, we set the record ID to be deleted and build the SQL statement using the DELETE query. Then, we use the mysqli_query() function to perform the delete operation and check if it was successful. Finally, we use the mysqli_error() function to capture and output any error messages and use the mysqli_close() function to close the database connection.

It should be noted that we must be careful when implementing the delete operation. We should always use DELETE query with WHERE clause to ensure that the correct records are deleted, otherwise the entire table will be deleted. Additionally, we should always back up the database to prevent any unexpected data loss.

In short, deleting table records is a very useful operation in PHP programming. In this article, we learned how to delete records from a database table using PHP code. We provide a simple demonstration example and explain how to use DELETE query. Hope this tutorial helps you!

The above is the detailed content of How to delete records from database table via PHP code. For more information, please follow other related articles on the PHP Chinese website!