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Normalization in Database Management System
- 1. NORMALIZATION IN DBMS Ms.Mary Sanjana Joseph Department of Computer Science(UG) Kristu Jayanti College(Autonomous) K.Narayanapura ,Kothannur Bengaluru-560077
- 2. NORMALIZATION • Normalization isthe process of organizing the data in the database. • Minimize the redundancy from a relation. • Eliminate undesirable characteristics like Insertion, Update, and Deletion Anomalies. • Normalization divides the larger table into smaller and links them using relationships.
- 3. ANOMALIES • Insertion Anomaly: Cannotinsert a new tuple into a relationship due to lack of data. • Deletion Anomaly: The deletion of data results in the unintended loss of some other important data. • Updation Anomaly: Updation of a single data value requires multiple rows of data to be updated.
- 4. UPDATION ANOMALY Imagine wehave a simple database for a small library. The library keeps track of books and the authors who write them. Book Author Email Programming in C Balaguruswamy balaguru@example.c om Programming in C++ Balaguruswamy balaguru@example.c om OOP in Java Balaguruswamy balaguru@example.c om Learning Python Alice Smith alice@example.com Java Basics Bob Brown bob@example.com The Great Novel Smith Brown sm@example.com
- 5. INSERTION ANOMALY Adatabase table for storing information about employees and the departments they work in. The table is called Employee. Suppose you need to add a new department But you haven’t hired any employees for it yet. Let's say the new department is "Marketing" located in "Chicago". Since we don’t have any employees in this department yet, Still want to record the existence of this department in the database Employee Id Employee name Depatment Deptment Loc E01 Alice Smith IT India E02 Bob Brown HR New York E03 Smith Brown IT India
- 6. NULL NULL MARKETINGChicago
- 7. 1NF A relationis in 1NF if it contains an atomic value. StudentID StudentName Courses S01 John Doe Math, Science S02 Jane Smith History, Math S03 Mark Lee Math
- 8. NORMALIZED TABLE IN1NF StudentID StudentName Courses S01 John Doe Math S01 John Doe Science S02 Jane Smith History S02 Jane Smith Math S03 Mark Lee Math
- 9. 2NF • In the2NF, relational must be in 1NF. • In the second normal form, all non-prime key attributes are fully functional dependent on the prime key(Candidate key)
- 10. Student ID CIDStudent Name Course Name Instructor S01 c1 Mary Maths Alice S02 c2 Joseph Science Bob S03 c3 Ann English John Student ID Student Name S01 Mary S02 Joseph S03 Ann CID CourseNam e Instructor c1 Maths Alice c2 Science Bob c3 English John Student ID CID S01 c1 S02 c2 S03 c3
- 11. 3NF Should bein 2NF No transitive dependency. Eg: AB->C C->D, where AB are the prime attributes
- 12. Student ID CIDStudent Name Course Name Instructor S01 c1 Mary Maths Alice S02 c2 Joseph Science Bob S03 c3 Ann English John Student ID Student Name S01 Mary S02 Joseph S03 Ann CID CourseName Instructor c1 Maths Alice c2 Science Bob c3 English John Student ID CID S01 c1 S02 c2 S03 c3
- 13. IF CIDand Course Name can only produce the instructor Where CID is the prime attribute but Course name not a prime attribute then it is a transitive dependency