1.What are the differences and similarties between Entity Relationship Diagram, Data Flow Diagram and Use Case Diagram? 2. Where can be used? I have no idea with this. It is my assignment, but I try to google without explaination.
These are different visualisations of entities (for instance tables, or rows in tables in a database),of data flow (how data is input and fetched from the database), and use cases are specific ways the data is used in the application. For instance a new user is entered into the database via a form, and when you view a list of the users registered in the database, you'll also see the latest added user.