MySQL UUID vs INT for Primary Key

This blog familiarizes you to MySQL UUID, demonstrations you to use it as the primary key for a table and discusses the pros and cons of with it as the primary key.

Overview to MySQL UUID

UUID stands for Universally Unique IDentifier. UUID is defined built on RFC 4122, “a Universally Unique Identifier (UUID) URN Namespace).

UUID is considered as a number that is unique globally in space and time. Two UUID values are likely to be distinct, even they are created on two independent servers.

In MySQL, a UUID value is a 128-bit number characterized as a utf8 string of five hexadecimal numbers in the subsequent format:

To create UUID values, you use the UUID() function as tracks:

The UUID() function returns a UUID value in agreement with UUID version 1 described in the RFC 4122.

For example, the subsequent statement uses the UUID() function to produce a UUID value:

MySQL UUID vs. Auto-Increment INT as primary key


Using UUID for a primary key brings the subsequent rewards:

  • UUID values are unique crosswise tables, databases, and even servers that let you to merge rows from changed databases or allocate databases across servers.

  • UUID values do not expose the info about your data so they are harmless to use in a URL. For example, if a customer with id 10 entrees his account via URL, it is easy to guess that there is a customer 11, 12, etc., and this could be a target for an attack.

  • UUID values can be created anywhere that evade a round trip to the database server. It also make things easier logic in the application. For example, to insert data into a parent table and child tables, you must insert into the parent table first, get created id and then insert data into the child tables. By using UUID, you can create the primary key value of the parent table up front and insert rows into mutually parent and child tables at the same time within a transaction.


As well the advantages, UUID values also come with some drawbacks:

  • Storing UUID values (16-bytes) takes more storage than integers (4-bytes) or even big integers(8-bytes).

  • Debugging appears to be more tough, visualize the expression WHERE id = 'df3b7cb7-6a95-11e7-8846-b05adad3f0ae' instead of WHERE id = 10

  • Using UUID values may source routine issues due to their size and not being ordered.

MySQL UUID solution

In MySQL, you can store UUID values in a compact format (BINARY) and display them in human-readable format (VARCHAR) with help of the subsequent functions:




Notice that UUID_TO_BIN(), BIN_TO_UUID(), and IS_UUID() functions are only available in MySQL 8.0 or later.

The UUID_TO_BIN() function converts a UUID from a human-readable format (VARCHAR) into a compact format (BINARY) format for storing and the BIN_TO_UUID() function converts UUID from the compact format (BINARY)to human-readable format (VARCHAR) for displaying.

The IS_UUID() function returns 1 if the argument is a valid string-format UUID. If the argument is not valid string format UUID, the IS_UUID function returns 0. In case the argument is NULL, the IS_UUID()function returns NULL.

The following are the valid string-format UUID in MySQL:

MySQL UUID example

Let’s take a look at an example of using UUID as the primary key.

The following statement creates a new table named customers:

To insert UUID values into the id column, you use UUID() and UUID_TO_BIN() functions as follows:

To query data from a UUID column, you use BIN_TO_UUID() function to change binary format to human-readable format:

In this blog, you have learned about MySQL UUID and how to use it for the primary key column.

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