The data model describes how the data are stored in the database and related to each other. It also gives a view that how the relationship is established between them. The data model also defines how the logical structure of the database is created. The data model organizes schema and stores the data in the databases.
The data model consists of two parts logical design and physical design. We can say these data models that are used by database designers to develop databases, are the cornerstone of the design.
For example, an engineer prepares a model of a house before constructing it, similarly, database designers create data models to improve database design. The main purpose of the data model is to communicate and specify the concept of the database structure.
The main objective of the data model is to give an idea about the database structure when it is completed.
The advantage of Data model are
I) increased effectiveness – The data model increases the effectiveness of the database. Because the data it contains is very real, reliable, and extensible.
II) Reduced costs – We can build database applications through data models at a very low cost. For the data model, we have to spend only 10 percent of the project budget. With which we save 70 percent of the budget.
III) Simplicity – Data models are designed so that there is no problem in accessing the database. Its interface is very simple so most of them are able to use it easily.
IV) Minimum redundancy – Redundancy means “duplication of data” i.e. the same type of data being present in two places.
It is very harmful to have duplicate data that is stored unnecessarily in the database. The data models that are used greatly reduce redundancy.
V) Data integrity – data models do not allow any user to access the database without the owner’s permission. Any user can access the database only when he proves his integrity.
VI) In data independence – Data independence is a feature that provides independency of doing some changes in one level of the database, cannot affect that other level of the database. Such as, if we are doing some changes in the logical level of the database then it cannot affect the view level or physical level.
Types of DATA MODEL are as follows
- Hierarchical
- Relational
- Network
- Object-oriented
- E-R model