Data redundancy happens in databases systems which have an area that is persistent in two or more systems. Data redundancy causes information faults and computer data file corruption mistake error and generally should be avoided by design. With the use of foreign key you can minimize the proper use of data redundancy in your table. Because of Data redundancy lots of storage space are wasted. It's difficult to update the database because there is duplicate data in table. Data redundancy is inefficient and worthless for several aspects and databases designers try to eliminate it as far as possible by using a technique known as normalization. Database normalization prevents redundancy and makes the best possible use of storage space.
Database is good approach for storing the data. Data redundancy is data organization problem in which it is allow unnecessary data duplication in your database. This can be happen due to relational database management system.