Using Regular Expressions In Check Constraints

Denis Gobo shows that SQL Server check constraints support limited regular expression capabilities:

While SQL server does not support a full implementation of regular expression, you can do what the person asked for without a problem in T-SQL. Here is what the regular expression looks like

[DMOPT][0-9][0-9]

A constraint like that will allow allow the following alphabetic characters (D, M, O, P or T) followed by 2 numeric characters. Enough talking let’s look at some code, first create this table

Read on to see how this constraint works and for implementation code.

Related Posts

Missing Foreign Keys—A Cultural Problem

Martin Catherall tells a spooky Halloween story: By large databases I’m roughly meaning databases with several hundred tables, and I usually see a lot of these tables with several hundred GB’s of data in them. When I generally ask about the reason for no foreign key, I’m told they add  overhead they give no benefit […]

Read More

Natural Keys?

Steve Jones wonders if we should give up on natural primary key constraints: One of the things I think is important in modeling your particular entity is including a primary key (PK). In my DevOps talk I stress this, as I’d rather most attendees come away thinking a PK is important as their first takeaway […]

Read More

Categories

October 2017
MTWTFSS
« Sep Nov »
 1
2345678
9101112131415
16171819202122
23242526272829
3031