Data Models in DBMS
What is a Data Model?
A “Data Model” is the underlying structure of a database. To put it simply, Data Models organize data elements, their relationships to each other and real-world entities, and data semantics.
A Data Model gives a way to describe the design of the database at the Physical, Logical and View levels.
The four most commonly used types of Data Models are:
- Relational Model: The relational model segregates the data into tables called ‘relations’, consisting of rows and columns. Each table has multiple columns and each column has a unique name.
The rows are called ‘tuples’ and they consist of information related to the object
- Entity-Relationship Model: The E-R model uses a collection of basic objects(Entities) and relationships among those objects.
Entities can be any object that exists in the real world, like people, books, buildings, etc.
An attribute is the property of that object. For example, the entity ‘person’ has attributes like person-name, person-age, etc. The E-R diagram helps to represent the E-R Model.
- Object-based Data Model: This is an extension to the E-R model with concepts of encapsulation, methods and object identity. The objects are data elements carrying some properties.
- Semi-structured Data Model :
This model is a developed version of the relational model. In this data model, data storage is flexible and so are the attributes. It lacks a rigid schema and hence, entities of the same type are allowed to have different sets of attributes.