It is important to have an idea of the type of data needed before implementing a system. We can easily identify this data from the use case definitions we gave earlier. From our use case specifications, we can determine that two basic types of data are required. These are the user data and the message data. As the names imply, the user data is the data required of every user, and message data is the data pertaining to a message sent. We are not concerned with things such as schemas, entities, or entity relationship diagrams yet. We just require an idea of the data to be required by the system.
As this is a messenger app, the user we will require a username, phone number, password, and a status message. It will also be useful ...
