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Data Normalization

Data Normalization. Lecture Notes Spring 1998 (rev 2010). Data Normalization. Process of assigning attributes to entities Identifies and resolves anomalies of Insertion (adding new records) Deletion (removing existing records) Updating (modifying existing records). Normal forms.

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Data Normalization

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  1. Data Normalization Lecture Notes Spring 1998 (rev 2010)

  2. Data Normalization • Process of assigning attributes to entities • Identifies and resolves anomalies of • Insertion (adding new records) • Deletion (removing existing records) • Updating (modifying existing records)

  3. Normal forms • Several normal forms • Common usage • First normal form • Second normal form • Third normal form • Other forms • BCNF, 4th, 5th,…, DKNF

  4. First Normal Form • Column names are unique • No duplicate rows • All the key attributes are defined • determine your primary key • No repeating groups • Each row/column intersection contains one and only one value • All attributes are dependent on the primary key

  5. Second Normal Form • It is in First NF • Has no partial dependencies • No non-key attribute is dependent on part of the key • A relation with one attribute primary key is in 2NF • There is no partial dependency here!

  6. Third Normal Form • It is in Second NF • Has no transitive dependencies • No non-key attribute is dependent on another non- key attribute(s). • A relation with all keys is already in 3NF!

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