So far in this section we have discussed the types of functional dependency that are most useful in identifying important constraints on a relation and how these dependencies can be used to identify a primary key (or candidate keys) for a given relation. The concepts of functional dependencies and keys are central to the process of normalization. We continue the discussion on functional dependencies in the next chapter for readers interested in a more formal coverage of this topic. However, in this chapter, we continue by describing the process of normalization.