INT or Unique Identifier: Which ID Field Type Is Best for My Database?

Which Field Type Should You Use for an ID: INT or Unique Identifier?

When designing a database, one of the key decisions is the type of field to use for the ID field. Traditional choices include integers (INT) and unique identifiers (GUIDs).

Arguments for INT

Integer fields have several benefits:

• Smaller size: INTs are generally only 4 bytes, while GUIDs are 16 bytes. This can save space in the database.
• Faster queries and joins: INTs are faster to query and join than GUIDs because they can be directly compared. GUIDs must be converted to a format comparable to INTs before comparisons.
• Less risk of fragmentation: INTs increment sequentially, which reduces fragmentation in indexes. GUIDs, on the other hand, are more random and can lead to page splits and fragmentation.

Arguments for GUIDs

GUIDs have some advantages over INTs:

• Uniqueness: GUIDs are cryptographically generated, ensuring that they are unique even across multiple databases. They eliminate the risk of duplicate IDs.
• Usability in distributed systems: GUIDs are ideal for use in distributed systems where data must be transferred between different databases. They allow for easy identification of records and relationships.

Best Choice

In general, INTs are the preferred choice for ID fields with the following considerations:

• If you do not require absolute uniqueness across multiple databases.
• If you prioritize query speed and efficiency.
• If you are concerned about database fragmentation.

GUIDs are more suitable if you:

• Need to ensure uniqueness across multiple databases or systems.
• Work with data in a distributed environment.
• Require flexibility and adaptability in your data model.

However, as the provided expert opinion emphasizes, if you must use GUIDs as clustered keys, you should use sequential GUIDs to mitigate the issue of randomness and its impact on performance.

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