Relational database design unit(v)
- 1. • Paper Name -- Database System • Staff -- Ms. D. Saritha M.C.A., M.phil., • Class -- II Year • Semester -- IV • Unit -- V • Topic -- Relational Database Design
- 3. RELATIONAL DATABASE DESIGN Relational database design: The Relational database design is a collection of tables , each of which is assigned a unique name. The table contain rows and columns. Each row represents a record. Each column represents an attribute of data.
- 4. RELATIONAL DATABASE DESIGN Goal of Relational Database Design: To generate a set of relation schemas that allows as to store information without unnecessary redundancy, It also retrieve information easily. Normalization: Normalization is organizing a database to reduce redundancy and improve data integrity.
- 5. In normalization, the elements cannot be broken in small parts. It is an important part of relational database design. It is also reffered to as database normalization or data normalization Normalization helps speed, accuracy and efficiency of the database.
- 6. RELATIONAL DATABASE DESIGN Benefits of Normalization: It avoids the duplicate data. It minimizes the null values. It avoids data modification issues Normalization can simplifies queries.
- 7. Types of Normalization: The types of normalization are, First Normal Form(1NF) Second Normal Form(2NF) Third Normal Form(3NF) Boyce-Codd Normal Form(BCNF)
- 8. First Normal Form(1NF): First normal form sets the fundamental rules for database normalization and relates to a single table within a relatioanal database system. Every column in the table must be unique. The separate tables must be created for each set of related data.
- 9. Each table must be identified with a unique column called the primary key. The rows and columns cannot be duplicated. The intersection of rows and columns(each cell)of the table must have only a single value. Second Normal Form(2NF): It should be table is in the first normal form. There should be no partial dependency.
- 10. Third Normal Form(3NF): The third normal form relaxes this constraint slightly by allowing certain non trivial functional dependencies whose left side is not a super key. A relation schema R is in third normal form with respect to a set F of functional dependencies if, for all functional dependencies in F+ of the form α→β
- 11. α→β is a trivial functional dependency. α is a superkey for β Every attribute A in β- α is contained in a candidate key for R. Boyce-Codd Normal Form: It avoids all redundancy that can be discovered based on functional dependencies. α→β is a trivial functional dependency. α is a superkey for R.