Let's talk about how to use PHP code to modify the contents of the data table

In the process of using a website, application or management system, it is a very common requirement to modify the contents of the data table. Normally, we need to use database management tools or SQL statements to complete modification operations. This article will introduce the use of PHP code to modify the content of the data table.

1. Connect to the database

First, we need to connect to the database in code. Normally, we use Mysqli or PDO extensions to interact with the database. Taking Mysqli as an example, the code to connect to the database is as follows:

//设置连接参数
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

//创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

//检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
} 
echo "连接成功";

2. Modify the contents of the data table

Next, we can start modifying the contents of the data table. In this article, we assume that we need to modify a row of data in the data table named users.

1. Update data

Updating data usually requires the use of the UPDATE statement. The following is the code to use Mysqli to update data:

//更新数据
$sql = "UPDATE users SET username='newname',password='newpassword' WHERE id='1'";

if ($conn->query($sql) === TRUE) {
    echo "数据更新成功";
} else {
    echo "数据更新失败: " . $conn->error;
}

In the above code, we use the UPDATE statement to modify the user name and password to newname and newpassword respectively. At the same time, we set the WHERE condition to ensure that only the row of data with id 1 is modified. If the modification is successful, we will see the prompt "Data updated successfully". Otherwise, we will see specific error messages.

2. Insert data

In addition to updating data, we may also need to insert new data into the data table. Normally, we use the INSERT statement to complete this operation. The following is the code for inserting data using Mysqli:

//插入数据
$sql = "INSERT INTO users (username,password,email) VALUES ('test','testpwd','test@test.com')";

if ($conn->query($sql) === TRUE) {
    echo "数据插入成功";
} else {
    echo "数据插入失败: " . $conn->error;
}

In the above code, we use the INSERT statement to insert new data into the users data table. Among them, we only filled in the data in the three fields of user name, password and email. If the insertion is successful, we will see the prompt "Data Insertion Successful". Otherwise, we will see specific error messages.

3. Delete data

Finally, we may also need to delete specific data rows from the data table. Normally, we use the DELETE statement to complete this operation. The following is the code to use Mysqli to delete data:

//删除数据
$sql = "DELETE FROM users WHERE id='1'";

if ($conn->query($sql) === TRUE) {
    echo "数据删除成功";
} else {
    echo "数据删除失败: " . $conn->error;
}

In the above code, we use the DELETE statement to delete the row of data with id 1 from the users data table. If the deletion is successful, we will see a "Data deletion successful" prompt. Otherwise, we will see specific error messages.

3. Disconnect the database connection

After completing the modification of the data table content, we need to close the connection with the database to release system resources. The following is the code to use Mysqli to close the connection:

$conn->close();

IV. Summary

Through the above code examples, we have introduced the basic operations of using PHP code to modify the contents of the data table. It should be noted that in actual development, we need to strictly verify the input data to ensure the security and correctness of the data. At the same time, we should also choose appropriate extensions based on actual application scenarios to achieve the best performance and ease of use.

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