Different Data Models
Data models define how data is organized, stored, and accessed in a database management system (DBMS). Below
are explanations of four common data models with small examples.
Relational Model
The relational model organizes data into tables (relations) consisting of rows (tuples) and columns
(attributes). It uses keys to establish relationships between tables.
Example: A simple "Employees" table.
| ID | Name | Department |
|----|---------|------------|
| 1 | Alice | HR |
| 2 | Bob | IT |
| 3 | Charlie | Sales |
Hierarchical Model
The hierarchical model organizes data in a tree-like structure with parent-child relationships, where each
child has only one parent.
Example: Company organization chart.
CEO
├── Manager HR
│ └── Employee Alice
└── Manager IT
└── Employee Bob
Network Model
The network model allows more complex relationships where a child can have multiple parents, represented as a
graph with records and sets.
Example: Students and Courses (a student can enroll in multiple courses, a course can have multiple
students).
Student A ── Enrolls ── Course 1
Student A ── Enrolls ── Course 2
Student B ── Enrolls ── Course 1
Document Model
The document model stores data in flexible, semi-structured documents (e.g., JSON or XML), allowing nested
structures without a fixed schema.
Example: A user profile document.
{
"id": 1,
"name": "Alice",
"address": {
"street": "123 Main St",
"city": "Anytown"
},
"hobbies": ["reading", "traveling"]
}
