Menu
I'm trying to shift my design sensibilities from the LAMP stack to the Microsoft stack, and I just thought of something - when would I want to use a GUID? What benefits/drawbacks does it have compared to the old, reliable auto-incremented int?
617
Tables contain BOTH an auto-increment primary key integer id column AND a guid column. The guid can be used as needed to globally uniquely identify the row and id can be used for queries, sorting and human identification of the row.
An INT is certainly much easier to read when debugging, and much smaller. I would, however, use a GUID or similar as a license key for a product. You know it's going to be unique, and you know that it's not going to be sequential.
Having a guid column is perfectly ok like any varchar column as long as you do not use it as PK part and in general as a key column to join tables. Your database must have its own PK elements, filtering and joining data using them - filtering also by a GUID afterwards is perfectly ok.
A GUID is a "Globally Unique IDentifier". You use it anywhere that you need an identifier that guaranteed to be different than every other. GUIDs are generally used when you will be defining an ID that must be different from an ID that someone else (outside of your control) will be defining.
Your experience never having needed anything beyond autoincremental ids might suggest that GUIDs are often a solution in search of a problem. Use them when and if you ever run into a requirement where your familiar pattern doesn't work. The microsoftiness is irrelevant.
The only realistic scenario I've seen is merging tables from two sources.
131
One problem with GUIDs:
Because they are not sequential, the database will have to work hard to update indexes. With a sequential id, it can usually just append it to the end (more or less). Since GUIDs are random it has to fit it into an existing block. That said, we use GUIDs for some tables and they seem to work fine even under fairly heavy load.
36
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
