The discussions of what data items are needed in a system and how they flow. Here also discussed how a data dictionary is developed for a system. For designing database we need three things – entities, relationships and attributes. In database design it is necessary to develop a conceptual model of data which specifies the relationships between data. This is used to group data into a number of tables. The tables are organized to reduce duplication of data, simplify functions like adding, deleting and changing data in other words, updating data and select data required for processing, in other word, retrieving data. There is also another functionality of database design is normalization. The methods of organizing or structuring data into tables are known as normalization. The normalized database is later converted to a physical database.