DBMS PROJECT.pptx (with normalization upto 3nf)
- 2. PROBLEM STATEMENT Attendance Management System is designed to record, track, and manage student attendance data for an educational institution. It provides functionality for teachers to mark attendance, view attendance records, and generate reports. The system will help ensure students maintain the required attendance percentage and make it easier to track attendance trends for different classes and subjects. Objectives: • Record attendance for students in various classes and subjects. • Generate reports to display students' attendance percentage. • Ensure attendance integrity through proper constraints. • Enable queries to retrieve and manage attendance records. •
- 3. INTEGRITY CONSTRAINTS 1.Entity Integrity: • Each table has a primary key that uniquely identifies each record. • No field in a primary key is NULL. 2.Referential Integrity: • Foreign keys are properly defined to ensure relationships between tables are maintained. • When a referenced record (such as a student or course) is deleted, the dependent records are handled properly to maintain the consistency of the database. 3.Domain Integrity: • The values in each column are of the correct type and format. For example, the attendance status can only be present or absent (no other value). • Fields such as Date for the attendance should follow a proper date format. 4.Key Constraints: • The ID (student id) in the tblstudents table and ID (course id) in the Courses table must be unique. • ID (student id) and ID (course id) combinations in the tblattendance table must be unique for each date. 5.Check Constraints: • Ensured that the Date field in the attendance record does not accept future dates. 6. Logical Constraints: • The attendance of a student can never be greater than 100% or less than 0%. • Student must be enrolled in the class to mark attendance
- 5. Introduction to Normalization • Database normalization is the process of organizing data to reduce redundancy and improve data integrity. • Benefits of Normalization: • - Reduces redundancy • - Improves data integrity • - Ensures efficient data handling
- 6. First Normal Form (1NF) • 1NF requires: • - Each field contains only atomic values • - Unique rows • - A primary key for each table • No Multivalued and Composite variables. • Example:
- 7. NAME FNAME LNAME Multivalued Attribute Dividing Name into Fname makes the name attribute atomic in nature
- 8. Second Normal Form (2NF) • 2NF requires: • - 1NF is satisfied • - No partial dependency • - All non-key attributes fully functional dependent on the primary key • Example:
- 9. Example - In this ATTENDANCE TABLE we see how 2NF is Implemented- •Key-Attributes- Id (Primary Key) •Non Key- Attributes- admissionNo, classId, classArmId, sessionTermId, status, date TimeTaken. •Since Id is the primary key, each non-key column ( e.g., admissionNo, classId, classArmId, etc.) is fully dependent on Id (the primary key).There is no indication of partial dependency here, as each attribute relates to the student’s record uniquely identified by Id. •This table already satisfies 1NF as all columns have atomic values
- 10. Third Normal Form (3NF) • 3NF requires: • - 2NF is satisfied • - 1NF is satified • - No transitive dependency • - Non-key attributes should not depend on other non-key attributes • Example:
- 11. ID These all Non-Key Attributes are not dependent on each other. • "In this table, none of the non-key attributes, like admissionNo, classId, classArmId, etc., depend on each other. •For example, classId doesn’t determine sessionTermId, and status doesn’t depend on date. Each attribute provides specific information about the student identified by the Id field and only depends on this primary key." "For the table to be in 3NF, it must already be in 2NF, and there should be no transitive dependencies.
- 12. Database Tables and Explanation • Tables Overview and Relationships: • The following tables represent a normalized database structure with clearly defined primary and foreign keys.
- 13. This is the Designer View of the Database showing relation between tables like foreign key references. •PRIMARY KEY
- 14. Conclusion • Normalization Benefits Achieved: • - Improved data integrity • - Reduced redundancy • - Easier maintenance • - Enhanced data structure • This database is normalized up to 3NF, ensuring efficient and reliable data organization.