Unique Contraint/Index Based On Values

I have a table that has the following column definitions:

ID (INT, PK)
Name (VarChar)
Active (Bit)
Bunch_of (Other_columns)

Question: I want to have a Constraint on Name/Active such that we can only have 1 record with a given Name that is Active (Active = 1), but we could have many records that have the same Name that are Inactive (Active = 0). Is this possible?

I’ve tried the normal Unique constraints, but they limit the dataset to only allow 1 record with a given Name to be Inactive.

To enforce this declaratively in 2005 you can use an indexed view.

CREATE VIEW dbo.ActiveNames
WITH SCHEMABINDING
AS
SELECT Name
FROM  dbo.YourTable
WHERE Active = 1

GO

CREATE UNIQUE CLUSTERED INDEX UQ_ActiveNames ON dbo.ActiveNames(Name)

This can be done using CHECK constraint which execute function. Didn’t test it completely but it works fine in my initial tests. Here is working eg.

CREATE function fn_checkNA(
@name varchar(6) )
 Returns smallint
 as 
  Begin
   Declare @c smallint
    if (select count(1) from dbo.chktest where Name = @name and Active = 1) > 1
     Set @c = 1
    else
     set @c = 0
   Return @c
  End

Create table :

create table chktest( ID INT primary key,Name VarChar(6) CONSTRAINT chkname CHECK(dbo.fn_checkNA(Name) = 0)
,Active Bit )

Now try to run below insert.

 insert into chktest values(1,'James', 0)
  insert into chktest values(2,'James',1)
  insert into chktest values(3,'James',0)
  insert into chktest values(4,'James',1)  --- This fails

Please test thoroughly before using this method.

NJ