Explain the steps to add and delete in php

In the process of web development, PHP is often used for website backend development, so how to add and delete data in the database? The steps for adding and deleting php will be introduced below.

1. Add data in php

1. Connect to the database

First, you need to connect to the database in the php file and use the mysqli_connect method to establish the connection. The specific code is:

//定义数据库连接变量
$servername = "localhost";//服务器名
$username = "username";//用户名
$password = "password";//密码
$dbname = "mydatabase";//数据库名称

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

// 检测连接
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}

2. Build a SQL statement

Next, you need to build a SQL statement and insert data into the database. The specific steps are as follows:

$sql = "INSERT INTO table_name (column1, column2, column3) VALUES (value1, value2, value3)";

Among them, table_name is the table name, column1, column2 and column3 is the column name in the table, value1, value2 and value3 are the values ​​inserted into the corresponding columns.

Modify the above code and insert a specific example. The code is as follows:

$sql = "INSERT INTO user (username, age, sex) VALUES ('Tom', 20, 'male')";

3. Execute the SQL statement

Finally, execute the constructed SQL statement. The specific code is:

if (mysqli_query($conn, $sql)) {
    echo "添加记录成功";
} else {
    echo "添加记录失败: " . mysqli_error($conn);
}

After successful execution, the message "Record added successfully" will be output.

2. Delete data in php

1. Connect to the database

You also need to connect to the database in the php file first, and the method is the same as adding data.

2. Construct a SQL statement

Construct a SQL statement to delete data. The specific code is as follows:

$sql = "DELETE FROM table_name WHERE some_column = some_value";

Among them, table_name is the table name, and some_column is the location where the data needs to be deleted. Column name, some_value is the value corresponding to this column.

Modify the above code to delete the data named Tom in the user table. The code is as follows:

$sql = "DELETE FROM user WHERE username = 'Tom'";

3. Execute the SQL statement

Finally, execute the constructed SQL statement, The specific code is:

if (mysqli_query($conn, $sql)) {
    echo "删除记录成功";
} else {
    echo "删除记录失败: " . mysqli_error($conn);
}

After successful execution, the message "Record deleted successfully" will be output.

Summary

This article introduces the method of adding and deleting data in PHP. It should be noted that connecting to the database and executing SQL statements are both necessary. In actual development, you can refer to the above code to modify and use it accordingly to better implement data operations.

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