Briefly describe the following concepts and answer the questions.

(i) What is Update Anomaly in databases? What are the consequences if the Update Anomaly happens to a database?

(ii) What is a Foreign Key? How important are the foreign keys in a relational database?

(iii) What is a Tuple in relational database? Should a tuple be unique within a relational database? If yes, how is the uniqueness of tuples maintained?

(iv) What is an Attribute Closure? What is it used for?

(v) What does it mean if a relation is in 2NF?

(vi) In designing a relational database model, what is the normalization process used for?

(vii) In SQL programming, what is an aggregation query?

(viii)What is a DBMS used for?