part 1: The company “Visitors” wants a website for a guestbook. They want the guestbook to work so that it can create and delete posts.
The guestbook should contain the entries

who made the post (name or alias),
The post (the text that was written) and
date and time when the post was made.
The created posts should be stored in a text file in serialized form.
NOTE! You do not need to be able to update these posts, but it is enough to create new and delete any posts.

Your solution should be object oriented with PHP and be able to store / read all information against a serialized file on your server.
The features to be implemented in your solution on the guestbook website should be:

possibility to create and delete posts in the guestbook
Information that should be in each record should be:
username / signature, post, date + time for created post

Part 2:

Following a request from the client, they want to change the storage of the posts to work against a database instead of storage against a text file.
It is your job to implement this solution.

The created posts should be stored in a relational database where each post is stored as a separate record.

Your solution should be object oriented with PHP and be able to store / read all information against a database on a server.
The features to be implemented in your solution on the guestbook website should be:

possibility to create and delete posts in the guestbook
Information that should be in each record should be:
User name / signature, post, date + time for created post
The interface to the site is up to you to create using HTML, JavaScript and style templates where the appearance may be optional.
Keep in mind that you should be able to test all features of your solution from this interface.