What are different normalization forms?


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hemant kumar
What are different normalization forms?
1 Answer(s)      7 years ago
Posted in : SQL

What are different normalization forms?

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November 18, 2010 at 4:57 PM


1NF: Eliminate Repeating Groups- Make a separate table for each set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.

2NF: Eliminate Redundant Data- If an attribute depends on only part of a multi-valued key, remove it to a separate table.

3NF: Eliminate Columns Not Dependent On Key- If attributes do not contribute to a description of the key, remove them to a separate table. All attributes must be directly dependent on the primary key

BCNF: Boyce-Codd Normal Form- If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.

4NF: Isolate Independent Multiple Relationships- No table may contain two or more 1:n or n:m relationships that are not directly related.

5NF: Isolate Semantically Related Multiple Relationships There may be practical constrains on information that justify separating logically related many-to-many relationships.



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