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Database Normalization

Database Normalization. Dr. Mahendra Jivraj Patel Templesoft Solutions Pvt. Ltd. www.templesoft.com. Data. Primary Key. A primary key is a field, or list of fields, that uniquely identify one record. Employee_Project Table. Primary Key. Project Number cannot be a Primary Key

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Database Normalization

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  1. Database Normalization Dr. Mahendra Jivraj Patel Templesoft Solutions Pvt. Ltd. www.templesoft.com

  2. Data

  3. Primary Key • A primary key is a field, or list of fields, that uniquely identify one record

  4. Employee_Project Table

  5. Primary Key • Project Number cannot be a Primary Key • Neither can the Employee Number be the Primary Key • Both do not identify a row uniquely • Both together are the Primary Key for this table

  6. Employee_Project Table

  7. Normalization • There are 5 Normal Forms • Only 3 are used in commercial application • Normalization is done to maintain the integrity of data • Sometimes tables are De-Normalized for efficiency – faster reports

  8. 1st Normal Form • Eliminate repeating groups • All key attributes are defined • All attributes are dependent on the primary key

  9. 2nd Normal Form • The table HAS to be in the 1st Normal Form • The attribute should be related to the entire Primary Key • No partial dependency

  10. Data • Project Name is dependent ONLY on Project Number • Employee Name, Rate Category and Hourly Rate are dependent ONLY on Employee Number • Remove these fields from the Table

  11. Employee_Project Table

  12. Project Table

  13. Is this appropriate? Employee Table

  14. 3rd Normal Form • The table HAS to be in the 2nd Normal Form • There should be no transitive dependencies • Where a non-key attribute is dependent on another non-key attribute • Each column must be DIRECTLY dependent on the primary key

  15. Employee Table

  16. Rate Table

  17. Any Questions? Thank You vrgurus@hotmail.com mjp@templesoft.com

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