Assignments - Database Management System
1. Explain Different data models with an Example
Data models are conceptual representations of how data is organized and structured. They provide a blueprint for storing, managing, and retrieving data in a database or data storage system. There are several types of data models, each with its strengths and weaknesses. Here are some common data models with examples:
- Relational Data Model
- Hierarchical Data Model
- Network Data Model
Relational Data Model
A relational data model organizes data into tables with well-defined relationships between them. Each table has rows and columns, where each row represents a single record and each column represents a field or attribute of that record.
Students Table
| StudentID (Primary Key) | Name | Age | DepartmentID (Foreign Key) |
|---|---|---|---|
| 1 | John Doe | 20 | 1 |
| 2 | Jane Smith | 22 | 2 |
| 3 | Bob Johnson | 21 | 1 |
Courses Table
| CourseID (Primary Key) | CourseName | DepartmentID (Foreign Key) |
|---|---|---|
| 1 | Math 101 | 1 |
| 2 | Science 202 | 2 |
| 3 | History 303 | 1 |
Hierarchical Data Model
A hierarchical data model organizes data into a tree-like structure, with each node representing a record or a group of records.
Company
Network Data Model
A network data model organizes data into a graph structure, with each node representing a record or a group of records, and edges representing relationships between them.
2. What is An ER Diagram? Write its notation and draw ER diagram for Library Management System
An Entity Relationship (ER) Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system.
Refer to:
Diagram: Link
