Introduction
Database design is the process of creating a database that meets the needs of an organization. A well-designed database is efficient, reliable, and easy to use.
Key Principles
- Normalization: Reducing data redundancy and dependency. This involves organizing data into tables in such a way that minimizes duplication.
- Data Types: Selecting appropriate data types for each column to ensure data integrity and efficiency.
- Relationships: Defining relationships between tables to represent how data is connected. These can be one-to-one, one-to-many, or many-to-many.
- Primary Keys: Identifying unique identifiers for each record in a table.
- Foreign Keys: Establishing relationships between tables by referencing primary keys in other tables.
Normalization Forms
Different normalization forms exist, each representing a different level of data redundancy reduction:
- 1NF (First Normal Form): Each column contains only atomic values.
- 2NF (Second Normal Form): Must be in 1NF and all non-key attributes must be fully functionally dependent on the primary key.
- 3NF (Third Normal Form): Must be in 2NF and all non-key attributes must be independent of each other.
Example: E-commerce Database
Let's consider a simple e-commerce database. It might include tables like:
Customers(CustomerID, Name, Address, Email)Products(ProductID, Name, Description, Price)Orders(OrderID, CustomerID, OrderDate)OrderItems(OrderID, ProductID, Quantity)
This example demonstrates how tables are related to represent product information and customer orders.