Database-wide unique-yet-simple identifiers in SQL Server

Question

First, I\'m aware of this question, and the suggestion (using GUID) doesn\'t apply in my situation.

I want simple UIDs so that my users can easily communicate this i

Answer 1

You could use an autoincrement column to generate the unique id. Then have a computed column which takes the value of this column and prepends it with a fixed identifier that reflects the entity type, for example OR1542 and DL1542, would represent order #1542 and delivery #1542, respectively. Your prefix could be extended as much as you want and the format could be arranged to help distiguish between items with the same autoincrement value, say OR011542 and DL021542, with the prefixes being OR01 and DL02.

Answer 2

Maybe an itemType-year-week-orderNumberThisWeek variant?

o2009-22-93402

Such identifier can consist of several database column values and simply formatted into a form of an identifier by the software.

Answer 3

We faced a similar problem on a project. We solved it by first creating a simple table that only has one row: a BIGINT set as auto-increment identity. And we created an sproc that inserts a new row in that table, using default values and inside a transaction. It then stores the SCOPE_IDENTITY in a variable, rolls back the transaction and then returns the stored SCOPE_IDENTITY.

This gives us a unique ID inside the database without filling up a table.

If you want to know what kind of object the ID is referring to, I'd lose the transaction rollback and also store the type of object along side the ID. That way findout out what kind of object the Id is referring to is only one select (or inner join) away.

Answer 4

Handle it at the user interface--add a prefix letter (or letters) onto the ID number when reporting it to the users. So o472 would be an order, b531 would be a bill, and so on. People are quite comfortable mixing letters and digits when giving "numbers" over the phone, and are more accurate than with straight digits.

Answer 5

Why not a simple Base36 representation of a bigint? http://en.wikipedia.org/wiki/Base_36

Answer 6

MS's intentional programing project had a GUID-to-word system that gave pronounceable names from random ID's