GUID vs INT as a primary key in enterprise databases

Question

When should you use GUID vs INT as a primary key in enterprise databases?

Amit Mohanty · Answer

Use INT/BIGINT as a primary key when you want maximum performance, small indexes, and all inserts come from a single database. Use GUID when you need globally unique IDs, client-side key generation, distributed inserts, or unguessable identifiers (e.g., for APIs or replication).

Sandhiya Priya · Answer

Use INT/BIGINT as a primary key when you want maximum performance, smaller indexes, and simple sequential IDs in a single database. Use GUID (UniqueIdentifier) when you need globally unique IDs, distributed inserts, client-side key generation, or unguessable identifiers across multiple systems Comparison: GUID vs INT as Primary Keys Criteria INT / BIGINT GUID (UniqueIdentifier) Size 4 bytes (INT), 8 bytes (BIGINT) 16 bytes Performance Faster inserts, smaller indexes, better cache efficiency Slower inserts, larger indexes, more fragmentation Uniqueness Unique only within one database Globally unique across systems Generation Typically auto-increment (IDENTITY) or sequence Generated anywhere (client/server), no central coordination Portability Easy to debug, readable IDs Harder to read/debug, but safe to expose publicly Best Use Case Single-system apps, high-performance OLTP, small-medium datasets Distributed systems, replication, offline inserts, APIs needing unguessable IDs When to Use INT/BIGINT High-performance transactional systems where speed and index size matter. Single database environments with centralized inserts. Applications needing sequential, human-readable IDs (e.g., invoice numbers). Large datasets where storage efficiency is critical. When to Use GUID Distributed systems where multiple servers or clients generate IDs independently. Replication scenarios where uniqueness across databases is required. Security-sensitive contexts where IDs should not be guessable (e.g., public APIs). Offline or mobile apps that need to generate keys without connecting to the central DB.

Cynthia Sathuragiri · Answer

Use GUID when you need IDs that are unique across systems, safe to expose publicly, or work well in distributed apps Use INT when you want faster performance, smaller indexes, easier debugging, and simple IDs in a single system.

Sam Hobbs · Answer

An Int uses 4 bytes and a GUID uses 16 bytes unless expressed as a string. Not a big difference. If you use an int as the primary key then everywhere it is used as a foreign key will use less space. You could use both. You could use Int as a primary key and make a separate field that is a GUID. You can create an index on the GUID field.

Carl Walker · Answer

INT is faster, smaller, and ideal when all data is created in one system. GUIDs are useful when multiple systems generate records and you need guaranteed uniqueness, but they add overhead and can slow indexing. If everything stays local, INT works best; if data comes from different sources, GUID may be worth the trade-off.

GUID vs INT as a primary key in enterprise databases

Insert Link

Embed YouTube Video

Table Options

Insert Image

Answers (5)