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Database Normalization

Database Normalization. Prepared by: Dr. Samir Tartir. Definition. Normalization is the process of removing redundant data from your tables in order to improve: storage efficiency data integrity scalability. Goals. Eliminating redundant data

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Database Normalization

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  1. Database Normalization Prepared by:Dr. Samir Tartir

  2. Definition • Normalization is the process of removing redundant data from your tables in order to improve: • storage efficiency • data integrity • scalability

  3. Goals • Eliminating redundant data • For example, storing the same data in more than one table) • Ensuring data dependencies make sense

  4. Motivation • Minimize data redundancy • To make database structure flexible • Data should be consistent throughout the database • Insert Anomaly (explained later) • Update Anomaly • Deletion Anomaly • Complex queries required by the user should be easy to handle.

  5. Advantages • More efficient data structure. • Avoid redundant fields or columns. • More flexible data structure i.e. we should be able to add new rows and data values easily • Better understanding of data. • Ensures that distinct tables exist when necessary. • Close modeling of real world entities, processes and their relationships.

  6. Disadvantages • You cannot start building the database before you know what the user needs. • Normalizing the relations to higher normal forms i.e. 4NF, 5NF the performance degrades. • It is very time consuming and difficult process in normalizing relations of higher degree. • Careless decomposition may leads to bad design of database which may leads to serious problems.

  7. What is a Normal Form? • A set of conditions that data must satisfy • First Normal Form (1NF) • Second Normal Form (2NF) • Third Normal Form (3NF) • Boyce-Codd Normal Form (BCNF) • Fourth Normal Form (4NF) • Fifth Normal Form (5NF) • Sixth Normal form (6NF)

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