Normalization in database
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This document discusses database normalization. It defines normalization as organizing data to eliminate redundant data and ensure data dependencies. The main goals are isolating data, reducing storage space, and making the database structure flexible. The document outlines the various normal forms from 1st normal form to Boyce-Codd normal form. It provides examples of transforming data from an unnormalized form to higher normal forms using a student database example.
Normalization in database
- 2. Disclaimer: This presentation is prepared by trainees of baabtra as a part of mentoring program. This is not official document of baabtra –Mentoring Partner Baabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt . Ltd
- 4. NORMALIZATION • The process of efficiently organizing data in a database. • Two goals of normalization process: Eliminating Redundant Data Ensuring data dependencies • Main objective: Isolate data Reduce the amount of database space Make database structure flexible Consistent throughout database
- 5. • Should not suffer from following anomalies. Update anomalies. Insertion anomalies. Deletion anomalies. S_No S_name S_address Course_opted 1 smith calicut php 2 turner kannur java 3 clark wayanad java 4 smith calicut Android
- 6. Normalization Stages • 1NF • 2NF • 3NF • Boyce-Codd Normal Form (BCNF or 3.5NF)
- 7. First Normal Form (1NF) • The values in each column of a table are atomic . • Each table has a primary key. • There are no repeating groups.
- 8. Second Normal Form (2NF) • Should be in 1NF. • Remove subsets of data that apply to multiple rows of a table and place them in separate tables. • Create relationships between tables.
- 9. Third Normal Form (3NF) • should be 2NF. • Has no transitive functional dependencies. • Remove columns that are not dependent upon the primary key. • To convert 2NF to 3NF, we again divide tables.
- 10. Boyce-Codd Normal Form(BCNF) • Should be 3NF. • Every determinant must be a candidate key. • All tables can have only one primary key • Candidate Key: Any attribute or a set of attributes together that has the eligibility to become a primary key.
- 11. TRANSFORMATION FROM UNF TO HIGHER NORMAL FORMS USING AN EXAMPLE Dep_no Dep_ name Stud_no Stud_ name Stud_ dob Stud_ age Course_ name Course_ fee 1 cse 101 Name 1 1990-1-01 23 java 5000 102 Name 2 1991-5-25 22 php 4000 103 Name 3 1992-3-01 21 Java,php 5000, 4000 2 ec 104 Name 4 1990-2-01 23 robotics 10000 105 Name 5 1991-3-01 22 circuits 15000 106 Name 6 1992-4-01 21 robotics 10000
- 12. Conversion to 1st Normal Form Dep_no Dep_ name Stud_no Stud_ name Stud_ dob Stud_ age Course_ name Course_ fee 1 cse 101 Name 1 1990-1-01 23 java 5000 1 cse 102 Name 2 1991-5-25 22 php 4000 1 cse 103 Name 3 1992-3-01 21 Java 5000 1 cse 103 Name 3 1990-2-01 21 php 4000 2 ec 104 Name 4 1991-3-01 23 robotics 10000 2 ec 105 Name 5 1992-4-01 22 circuits 15000 2 ec 106 Name 6 1990-1-01 21 robotics 10000
- 13. Conversion to 2nd Normal Form Dep_no Dep_name 1 cse 2 ec Fk_dept_id Fk_stud_id Course_name Course_fee 1 101 java 5000 1 102 php 4000 1 103 Java 5000 1 103 php 4000 2 104 robotics 10000 2 105 circuits 15000 2 106 robotics 10000 Stud_no Stud_name Stud_dob Stud_age 101 Name 1 1990-1-01 23 102 Name 2 1991-5-25 22 103 Name 3 1992-3-01 21 103 Name 3 1990-2-01 21 104 Name 4 1991-3-01 23 105 Name 5 1992-4-01 22 106 Name 6 1990-1-01 21
- 14. Course_ name Course_ fee java 5000 php 4000 robotics 10000 circuits 15000 Dep_no Dep_ name 1 Cse 2 ec Fk_dept_no Fk_Stud_no Fk_Course_name 1 101 java 1 102 php 1 103 Java 1 103 php 2 104 robotics 2 105 circuits 2 106 robotics Stud_no Stud_name Stud_dob 101 Name 1 1990-1-01 102 Name 2 1991-5-25 103 Name 3 1992-3-01 103 Name 3 1990-2-01 104 Name 4 1991-3-01 105 Name 5 1992-4-01 106 Name 6 1990-1-01 Conversion to 3nd Normal Form
- 16. Class_name Roll_no name Class_teacher Class a 1 smith Teacher a Class a 2 turner Teacher a Class b 1 clark Teacher b Class c 1 allen Teacher c Class_name Class_teacher Class a Teacher a Class b Teacher b Class c Teacher c Class_name Roll_no name Class a 1 smith Class a 2 turner Class b 1 clark Class c 1 allen A Case where The table is in 3NF but not in BCNF A Case where The table is in both in 3NF and BCNF
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