How to make a good database design? Why we should create a good design database? Database design is an essential skill of a software engineer. In some interviews, the interviewer can ask you a few questions about it. As far as I know, we have some database principles. There are a lot of definitions about them and you can search on google for more details. Based on my experience, I’ll write it simply.
After reading this article, you will understand things:
- What is a good database design? Why we should create a good design database? How to make a good database design?
- Design process
- Define and use some rules
- Normalization Rules
- Integrity Rules
- Column Indexing
- Some notes and advice when we design a database
Database Design Overview
Firstly, What is database design?
“Database Design is the organization of data according to a database model. The designer determines what data must be stored and how the data elements interrelate.” Source: wikipedia.org
Database design is a part of the Design Process when we develop software. Before doing database design, we have to complete software architecture (N-tier layer, Microservice, …) at the high-level. Database design is a very important step at the low-level. Design Process often creates by Senior Software Engineer or Software Architect who has a lot of experience in the IT field.
Development Process. Source: Internet.
With a medium or big system, we usually choose and combine some databases to achieve our purpose. We need to support transactions and relationships: MySQL or PostgreSQL or SQL Server. We need to save flexible data: MongoDB(unstructured data). Support caching (Redis: key-value, sorted set, list, …), support full-text searching(Elastic Search, …), and so on.
Depends on your project, you should choose and combine some databases appropriately and wisely. There’s not the best database, only have database appropriately. We should take advantage of databases and know the limit/issues of them. In this article, I’ll only write about DBMS(Database Management System): MySQL. The reason is it’s complex more than NoSQL database such as MongoDB, Redis, and so on.
In some projects, the Senior Software Engineer or Solution Architect could request to make a Class Diagram and ERD (Entity Relationship Diagram). What the difference between the Class Diagram and ERD?
- The class diagrams are **used to represent the main object or building block**of the system. They are used to **_show the relationship of one class with another _**and also represent the attributes of the system.
- However, and ERD is more of a database in the form of tables. They don’t show individual relationships but relationship sets as well as sets of entities. They show the type of information that needs to be stored in the database.
In my opinion, we should make ERD and don’t create Class Diagrams unless we have some special reasons. This depends on your project.
#erd #database-design #good-database-design #design-db-process #database
