Are you planning to use MySQL for a Web Based Application? In this article, you will learn if a MySQL Table needs any Primary Key.
You most likely want to know about the Primary Keys in MySQL if you are a Database Developer in a beginner stage. While a Primary Key uniquely identifies records in a Table, there may be cases when you don’t need to use a Primary Key for a Table.
Let’s proceed and learn how MySQL Table Primary Keys work. In this article, you will also learn additional factors involved in the subject.
Here is a brief Table of Content. You can click on the Links to jump to the specific sections of the article.
Table of Content
- Does MySQL Table need Primary Key?
- Introduction to MySQL
- What is a MySQL Table?
- Introduction to the Primary Key
What is MySQL?
In simple words, MySQL is a Tool that helps you manage Relational Database systems.
In this case, it is also known as Open Source because its source code is freely available for developmental purposes. In this case, a Relational Database has records stored in the form of Tables, Rows, and Columns.
Introduction to a MySQL Table
A Table in MySQL refers to a collection of records about a specific entity. For example, a Table named Students will hold information about the specific entity, That is the Students.
In simple words, in MySQL, a Table is used to store and organize data in Rows and Columns manner.
In MySQL, you can create a Table with the CREATE TABLE statement. For more information on how the CREATE TABLE statement works in MySQL, land on This Page.
What is Primary Key?
It refers to a routine, rule, configuration, or constraint That can identify a record in a Table, in a unique manner. In simple words, a Primary Key in a Table identifies records uniquely.
A Primary Key is used to pinpoint records in a Table. That being said, if you want to pick unique records in a Table or want to pick each record uniquely when required, you will need to set Primary Key for Tables.
Does MySQL Table need Primary Key?
For better Indexing and retrieval of Data, yes MySQL Table needs a Primary Key. However, if you set a Primary Key for a Table in MySQL, it may create one automatically. Otherwise, the creation of the Table may fail.
Also, some instances of Database Systems force you to set a Primary Key. For example, MariaDB has released a statement That helps you create a mandatory Primary Key, known as innodb_force_primary_key.
However, there are cases when a Primary Key is not required. For example, when you create a Table with logging Time series data, no need to set a Primary Key in such cases. Also, some DBMS(s) may allow ignoring primary keys for simple Tables That hold static records, in certain cases.
Also keep in mind That if a Table exists with no Primary Key defined, the system automatically generates a hidden clustered index. In this case, the system automatically sets Rows and IDs to make things easier for the unique identification of records in a Table, the same as Tables with a proper Primary Key.
MySQL versions such as MySQL 8.0 handles Primary Keys in a more manageable manner. In this case, MySQL 8.0 has a built-in variable That handles Primary Keys efficiently.
In this case, when you try to create a Table with no Primary Key, you will be prevented by MySQL 8.0. In this case, you can either set a Primary Key or will have the option to drop a unique Primary Identifier from another Table in the Database.
As addressed by many Database Developers, creating Tables without a Primary Key may create Indexing problems in the Database. In this case, if you have a large database That contains hundreds of Tables, you can use Tools That help you identify Tables without a Primary Key.
For more information on such Tools, please refer to This article.
So, do we need to set a Primary Key for a Table in MySQL?
To better manage and retrieve data from a MySQL Table, it is mandatory to set Primary Keys for Tables in a Database.
However, today’s modern DBMS(s) also enforce setting Primary Keys for Tables. Fin case users miss setting one, the DBMS manages to set one automatically.
In MySQL 8.0, you can use dedicated statements for defining and enforcing Primary Keys for Tables. This is good, especially to avoid indexing issues in Tables.