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COMPUTER SOFTWARE APPLICATION - CITS

Casual Users / Temporary Users
- Occasional database users seeking new information each time.
- Examples include middle or higher-level managers.
Specialized Users

- Sophisticated users who create specialized database applications.
- Applications might not fit traditional data-processing frameworks.
- Examples include computer-aided design applications.

ER Model & Diagram, Database Schema

The term “ER model” refers to the Entity-Relationship model, which serves as a data model at an elevated level.
Its purpose is to establish the definition of data components and their interconnections within a designated system.
It generates a conceptual blueprint for the database, creating a straightforward and easily manageable
representation of data.

In the practice of ER modeling, the arrangement of the database structure is visually represented through a
diagram termed as an entity-relationship diagram.
Why Use ER Diagrams In DBMS?

ER diagrams play a pivotal role in portraying the E-R model within a database, simplifying the process of
transforming them into relational structures (tables).
The significance of ER diagrams lies in their ability to model real-world objects, adding a layer of practicality to
their utility.
With no demand for technical prowess or hardware assistance, ER diagrams offer a user-friendly approach.
Even for individuals unfamiliar with complex concepts, these diagrams are highly accessible and uncomplicated
to generate.
ER diagrams offer a uniform approach to logically visualizing data, providing a standardized solution.
Symbols Used in ER Model
The ER Model is employed to conceptualize the system’s logical aspect from a data stance, encompassing these
symbols
- Rectangles: These rectangles are utilized to symbolize Entities within the ER Model.
- Ellipses: Ellipses are employed to represent Attributes in the ER Model.
- Diamonds: The diamond shape is used to portray Relationships among different Entities.

- Lines: Lines are utilized to depict associations between attributes and entities, as well as entity sets with
different types of relationships.
- Double Ellipses: Double ellipses are used to signify Multi-Valued Attributes.

- Double Rectangles: Double rectangles are employed to indicate a Weak Entity.
Components of ER Diagram
Entity
An entity can encompass various elements such as objects, classes, individuals, or locations. Within an ER
diagram, entities are symbolized using rectangular shapes.
Take into account an instance of an organization - a manager, product, staff member, department, and so forth
could be regarded as entities in this context.

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CITS : IT&ITES - Computer software application - Lesson 18 - 36