chapter four

4 Entities and attributes

 

In this chapter

  • You start the design and analysis phase in database design.
  • You learn about keys and common data types in databases.
  • You design your first few entities, identifying their attributes, primary keys, and data types of attributes.
What you need to know

You can find the database design covered in this chapter (so far it’s only entities and attributes) implemented in tools commonly used by practitioners, such as dbdiagram.io, and MySQL Workbench in the GitHub repository (https://github.com/Neo-Hao/grokking-relational-database-design). You can navigate to the chapter_04 folder, and follow the instructions in README.md to load the database design into corresponding tools.

The data types covered in this chapter are applicable to most RDBMS, such as MySQL, MariaDB, and PostgreSQL. If you are using another RDBMS such as SQL Server or SQLite, you need to make small modifications to the design by replacing certain data types with their equivalences specific to an RDBMS. Such information can be found in README.md in the chapter_04 folder.

4.1 Overview

In Chapter 3, you walked through an overview of the database design process, and went over the requirements gathering phase for the online store of The Sci-Fi Collective.

4.2 Entities and attributes

4.3 Keys

4.4 Data types

4.4.1 String data types: power of personality

4.4.2 Integers: numbering your way to success

4.4.3 Float like a butterfly, decimal like a data queen

4.4.4 Temporal Data Types: Time Flies When You're Querying

4.5 Summary