How to make UDF deterministic

I have a user defined function in SQL Server 2000 that splits a Name field into First, Last, Middle names. Originally I utilized the CHARINDEX function to find the spaces in the string. Since I then found out that function is by definition Non-deterministic that didn't work for me, so I re-wrote the function a bit differently.

I am using the function as a field's formula in my table structure. I need the ability to create an index on that field so need the function to be deterministic. Apparently there is still something about how I designed the function that causes it to be non-deterministic. The function code is below; if anyone can help point me in the right direction it'd be greatly appreciated.

ALTER function fSplitName_test
(
@.name varchar(100),
@.fname int)
returns varchar(55)
as

begin
declare @.Fname_position int, @.Lname_position int, @.Mname_position int, @.SplitName varchar(55), @.iint int, @.iLen int,
@.sChar char(1), @.sName varchar(55)

set @.name = ltrim(replace(@.name, ' JR', ''))
set @.sName = @.name
set @.ilen = len(rtrim(@.name))
set @.Fname_position = 0
set @.Lname_position = 0
set @.iint = 0

while @.iint <> @.ilen
begin
set @.schar = left(@.sName, 1)
begin
if @.schar = ' '
begin
if @.Fname_position = 0
set @.Fname_position = @.iint
else
set @.Lname_position = @.iint
end
set @.iint = @.iint + 1
set @.sName = right(@.sName, @.ilen - @.iint)
end
end
if @.fname = 1
begin
if @.fname_position <> 0
set @.SplitName = left(@.name, @.Fname_position)
else
set @.splitname = 'unkn'
end
else
begin
if @.fname = 2
begin
if @.lname_position <> 0
set @.SplitName = right(@.name, @.ilen - @.Lname_position-1)
else
set @.SplitName = right(@.name, @.ilen - @.fname_position)
end
else
begin
if @.fname_position + @.lname_position <> @.ilen and @.lname_position <> 0
begin
set @.SplitName = left(@.name, @.lname_position)
set @.splitname = right(@.splitname,len(@.splitname) - @.fname_position - 1)
end
else
set @.splitname = 'unkn'
end
end
return @.SplitName
endYou might get more response if you post this under the "Microsoft SQL Server" forum. This one's for generic SQL questions - I for one know nothing about SQL Server.|||what if a person has a lastname like this "DELA CRUZ"
can you post an example of the name parameter ex: "Michael Angelo Rodriguez" or "Michael Angelo Dela Cruz" coz as you can see on the 2 ex. it is hard to detemine the first name on the first example and last name on the latter the name should have a middle initial or comma perhaps.|||This is probably completely wrong, but I wouldn't put it past SQL Server to think that you were trying to modify the parameters. That would, of course, make the function non-deterministic. Try copying them to local variables.

Otherwise, the way to debug a problem like this is to break your function into small functions and verify that the small functions are all deterministic.sql