Normalization in DBMS: 1NF, 2NF and 3NF in Database
Normalization is a process of organizing the data in database to avoid anomalies of inserting, updating and deleting. After this method, a large table becomes small tables and defines relationships between them to identify the organizing data clearly. Normalization was developed by IBM researcher E.F.Codd in the 1970 s. Example: Emp_ID Emp Name Emp_Add DOB Age Emp_Dep 101 Anne London 1991.02.21 25 D001 101 Anne London 1991.02.21 25 D002 123 Jack Paris 1993.06.30 23 D890 166 Ola Rio 1992.05.06 24 D900 166 Ola Rio 1992.05.06 24 D004 We have to face these problems because the above table is not normalized. Update anomaly – There are two rows for employee Anne because she works in two departments in the company. If we want to change her address, we have to update