What are the Different Database Models ?
Database model defines the logical design of data. Database model describes the relation between different parts of data.
There are Four Database models:
- Hierarchical Model
- Network Model
- Relational Model
- Entity-Relationship Model
1. Hierarchic Database Model
This is one of the oldest type of database models. In this model data is represented in the form of records. Each record has multiple fields. All records are arranged in database as tree like structure.
The relationship between the records is called parent child relationship in which any child record relates to only a single parent type record.
2. Network Database Model
It replaced hierarchical network database model due to some limitations on the model. Suppose, if an employee relates to two departments, then the hierarchical database model cannot able to arrange records in proper place.
So network, database model was emerged to arranged non-hierarchical database. The structure of database is more like graph rather than tree structure.
3. Relational Database Model
In this model, the data is organized into tables which contain multiple rows ad columns. These tables are called relations. A row in a table represents a relationship among a set of values.
Since a table is a collection of such relationships, it is generally referred to the mathematical term relation, from which the relational database model derives its name.
4. Entity-Relationship Database Model
This model is based on perception of a real world that contains a collection of basic objects, called entities and of relationship among these objects and characteristics of an entity. It shows relationship between different entities.