After the database design, some problem may come out. The first thoughts about how to design a database may be influenced by a particular report or by a particular method of input. This can lead to a design that cannot cope with different requirements later on. It is important to think about the underlying data and design the database to reflect the information being stored rather than what you might want to do with the data in the short term.

Database design should try to adapt to change, must not only the immediate functional requirements.
The first Chapter show three basis types of problems, and four sample problem.

1.    Mishandling Keywords and Categories.
     
2.    Repeated Information.

3.    Designing for a Single Report.

For more details see the books.

After database design, If we know the problems of the system, we can do better.