WikiGalaxy
Data Models in DBMS
Introduction to Data Models
Data models define how data is connected, stored, and accessed in a database management system (DBMS). They provide a structured framework to organize data and ensure data integrity and consistency.
Hierarchical Data Model
The hierarchical model organizes data in a tree-like structure where each record has a single parent and multiple children. This model is suitable for applications with a clear hierarchy, such as organizational charts.
Network Data Model
In the network model, data is represented as a graph with nodes and edges. It allows more complex relationships by enabling multiple parent-child relationships, making it suitable for applications like telecommunications.
Relational Data Model
The relational model uses tables (relations) to represent data and their relationships. It is widely used due to its simplicity and support for SQL, which allows flexible querying of data.
Object-Oriented Data Model
This model integrates object-oriented programming principles with database technology. It supports complex data types and inheritance, making it ideal for applications requiring rich data representations.
Entity-Relationship Model
The ER model uses entities, attributes, and relationships to represent data. It is often used in the initial design phase to conceptualize the database structure before implementation.
-- Example of a simple relational model with SQL
CREATE TABLE Employees (
EmployeeID INT PRIMARY KEY,
FirstName VARCHAR(50),
LastName VARCHAR(50),
DepartmentID INT,
FOREIGN KEY (DepartmentID) REFERENCES Departments(DepartmentID)
);
CREATE TABLE Departments (
DepartmentID INT PRIMARY KEY,
DepartmentName VARCHAR(50)
);
Advantages of Relational Model
The relational model provides data independence, easy data retrieval, and strong integrity constraints, making it the most popular choice for modern applications.
Limitations of Hierarchical Model
While efficient for certain hierarchical data, this model lacks flexibility and can be challenging to manage when data relationships become complex.
Use Cases for Object-Oriented Model
Ideal for applications requiring complex data structures like CAD/CAM, multimedia, and scientific research, where traditional models fall short.
Console Output:
Tables created successfully
