21) Consider the following relational schemes for a library for a library database:
Book (Title, Author, Catalog_no, Publisher, Year, Price)
Collection (Title, Author, Catalog_no)
Which ofthe following functional dependencies:
I. Title Author —› Catalog no.
II. Catalog_no ---> Title Author Publisher Year
III. Publisher Title Year --> Price.
Assume {Author, Title) is the key for both schemes: Which of the following statements is true?

23) The employee salary should not be greater than Rs. 2000. This is

24) Which of the following contains a complete record of all activity that affected the contents of a database during a certain period off time

25) Updating a data base means

26) Which of the following contains complete record of all activity that affected the contents of a database during a certain period of time