To store the data in the database, we need some data structures. Hence to make the database more efficient we use complex data structures that we normally do not use. To make the systems efficient in terms of data retrieval, reduce complexity, developers use the data abstractions concept(Hiding the irrelevant information from the user).
To achieve this data abstraction we use data models in the database management systems.
Data Model is a collection of concepts or notations to describe data, structure
of the database, data constraints, data semantics, and data relationships.
Most Data Models also include a set of operations to manipulate the data in the database.
High-Level Conceptual Data Model
High-Level Conceptual Data Models represent the data in the same way that is similar to how people perceive the data.
Eg. Entity-Relationship Model
Important Terms:
Entity: Entity is a real-world object eg. Student, Employee, Department
Attributes: Attributes represent the properties of the Entity eg. student_name, student_address, etc.
Relationship: It represents the association among entities.
Record Based Logical Data Model
It represents the data such that user’s can understand but it still similar to the way data is stored in the computer.
There are three types of Record Based Logical Data Models:
1. Hierarchical Model
2. Network-based Model
3. Relational Model
Hierarchical Model:
In the Hierarchical model, the data is represented in a tree-like structure. And there is a single parent node for each node.
Network Model:
It can allow each node to have multiple parent and child nodes.
Relational Model:
It stores the data in the form of relations or tables.
Physical Data Model:
The Physical Data Model represents how our data is stored in the computer memory, how it is scattered and ordered in the memory, and how it would be retrieved from the memory.
Happy Learning:)
