PHP record addition, deletion and modification

With the development of the Internet, web applications have become a part of modern life. As one of the most popular Web programming languages, PHP plays an important role in Web development. In many web applications, adding, deleting, modifying, and querying data is one of the most commonly used functions. Therefore, this article will introduce some basic methods of adding, deleting and modifying PHP records.

1. Adding records

1. Insert records into the MySQL database

In PHP, you can use the following functions to insert records into the MySQL database.

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

Among them, $conn is a connection variable that connects to the MySQL server and selects the database. column1, column2 and column3 are the column names in the table and value1, value2 and value3 are the values ​​to be inserted into the database. This SQL statement inserts a new record and stores it in the table named table_name.

2. Obtain the ID of the newly inserted record

In MySQL, each table has an auto-incremented primary key, which is automatically assigned to the newly inserted record. You can use the following function to get the primary key value of the record just inserted.

$last_id = mysqli_insert_id($conn);

This function will return the ID (automatically generated ID) of the row inserted into the data table from the most recent query operation.

2. Record deletion

1. Delete records from MySQL database

You can use the following function to delete records from MySQL database:

mysqli_query($conn,"DELETE FROM table_name WHERE column_name='value'");

The above statement Records in the table named table_name whose column column_name is value will be deleted. Among them, $conn is the connection variable to connect to the MySQL server and select the database.

2. Delete files

In some cases, it is necessary to delete files stored on the server. Here's how to delete a file:

unlink("file.txt");

The above code will delete the file named file.txt. Please note that you need to ensure that the path to the deleted file is correct.

3. Record modification

1. Update the records in the MySQL database

You can use the following function to update the records in the MySQL database:

mysqli_query($conn,"UPDATE table_name SET column1='value1', column2='value2' WHERE column3='value3'");

This SQL The statement updates columns column1 and column2 with new values ​​value1 and value2.

2. Rename files

Sometimes you need to change a specific file name. The following is how to rename a file:

rename("oldfile.txt", "newfile.txt");

The above code renames the original file oldfile.txt to newfile.txt.

Summary

The above is the basic method of adding, deleting and modifying PHP records. These methods should cover most common operations in web applications, but not all operations are suitable for every application scenario. Therefore, in practical applications, it needs to be used flexibly according to specific conditions.

The above is the detailed content of PHP record addition, deletion and modification. For more information, please follow other related articles on the PHP Chinese website!