eConsultant - Database Design FAQ

Q1: What is Database Normalization?

Ans: Database Normalization is a series of steps followed to obtain a database design that allows for consistent storage and efficient access of data in a relational database. These steps reduce data redundancy and the risk of data becoming inconsistent.

Q2: What is the 1st Normal Form?

Ans: First normal form (or 1NF) requires that all column values in a table are atomic (e.g., a number is an atomic value, while a list or a set is not).

Q3: What is the 2nd Normal Form?

Ans: Second normal form (or 2NF) requires that there are no non-trivial functional dependencies of a non-key attribute on a part of a candidate key.

Q4: What is 3rd Normal Form?

Ans: Third normal form (or 3NF) requires that there are no non-trivial functional dependencies of non-key attributes on something else than a superset of a candidate key.

Q5: What is the easiest way to remember the above rules?

Ans: Every column of the table will depend on the the key, only the key and nothing but the key.

Q6: Are there times when the database should not be in 3rd Normal form?

Ans: Yes, when the database becomes very large (millions of rows), it might be easier for online response time to de-normalize some of the data.

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