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Tuesday, February 9, 2016

Important keywords about database normalization and normal forms

Important keywords about database normalization and normal forms / Define Normalization / Define Normal forms / Define 1NF, 2NF, 3NF etc./ What is normalization? / What is normal form?

Keywords that you need to know in Database normalization


Normalization Click to read more…

It is the process of organizing (or defining) the structure (the columns / attributes) of a relation (a table) in such a way to avoid data redundancy, and to avoid anomalies like insertion anomaly, deletion anomaly, and updation anomaly.

Normal Form – Click to read more…

Normal form is one the several stages a table can be defined to avoid redundancy and anomalies. Each stage handles anomalies or redundancies that would be possible at that level. We have 1NF (First Normal Form), 2NF (Second Normal form), 3NF (Third Normal Form), BCNF (Boyce-Codd Normal Form), 4NF (Fourth Normal Form), 5NF (Fifth Normal Form / Project-Join Normal Form), 6NF (Sixth Normal Form), and DKNF (Domain-Key Normal Form – 3NF, BCNF, 4NF, and 5NF are special cases of DKNF). Each of these normal forms handles anomalies or redundancies at that level to give a better database design.

1NF / First Normal Form Click to read more…

It is one of the several stages a table can be in. We would say that the table is in 1NF if all the attributes are Atomic attributes.

2NF / Second Normal FormClick to read more…

It is one of the several stages a table can be in when the following properties are satisfied by the table in question;
  • Relation (table) should be in 1NF
  • Every non-key attribute should fully functionally dependent on the primary key or whole key (composite primary key) of the table.

3NF / Third Normal Form Click to read more…

It is one of the several stages a table can be in when the following properties are satisfied by the table in question;
  • The table should be in 2NF
  • Every non-key attribute of the table is non-transitively dependent on each candidate key of the table. In other words, no non-key attribute should depend on another non-key attribute.

BCNF / Boyce-Codd Normal FormClick to read more…

It is one of the several stages a table can be in when the following properties are satisfied by the table in question;
  • The table should be in 3NF
  • Every determinant should be a candidate key. (i.e., every Left Hand Side (LHS) of a functional dependency should be a candidate key)

4NF / Fourth Normal Form – Click to read more…

5NF / Fifth Normal Form – Click to read more…


6NF / Sixth Normal Form – Click to read more…


DKNF / Domain-Key Normal Form – Click to read more…




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