What is normalization? What are different type of normalization?

What is denormalization ?

What is a candidate key ?

What are different types of joins and whats the difference between them ?

What are indexes and What is the difference between clustered and nonclustered
indexes?

How can you increase SQL performance ?

What is the use of OLAP ?

What’s a measure in OLAP ?

What are dimensions in OLAP ?

What are levels in dimensions ?