But this part of business logic has quite unusable data structure, simple Books and Multimedia entities.
For avoiding performance issues and difficulties in extending this part of application in the future, I decided to expand database structure.
So each author has an authors_type, for example:
- writer
- composer
- singer
- band
Movies and music have a genre. Also movies have a type:
- film
- cartoon
- anime
Also we should keep in mind next situations:
- movie has multiple genres
- author has multiple types (writer and producer)
- book has multiple authors
Now we can develop business layer for Books and Multimedia pages regarding to this database schema.

