Entity Relationship Model (ER model):
(i) In this database mo-ad., relationship are created by dividing the object into entity and its characteristics into attributes.
(ii) It was developed by Chen in 1976. This model is useful in developing a conceptual design for the database.
(iii) It is very simple and easy to design logical view of data. The developer can easily understand the system by looking at ER model constructed.

(i) The Relational Database model was first proposed by E.P. Codd in 1970. It is the most widespread data model used for database applications around the world.
(ii) The basic structure of data in relational model is tables (relations). All the information's related to a particular type is stored in rows of that table.
(iii) Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple (row in a relation (tabler).

(i) A data model describes how the data can be represented and accessed from a software after complete implementation
(ii) It is a simple abstraction of complex real world data gathering environment.
(iii) The main purpose of data model is to give an idea as how the final system or software will look like after development is completed.

The Database Management System can be divided into five major components as follows:
(i) Hardware
(ii) Software
(iii) Data
(iv) Procedures / Methods
(v) Database Access Languages

(i) A DBMS is a soft ware that allows us to create, define and manipulate database, allowing users to store, process and analyze data easily.
(ii) DBMS provides us with an interface or a tool, to perform various operations to create a database, storing of data and for updating data, etc.
(iii) DBMS also provides protection and security to the databases. It also maintains data consistency in case of multiple users.