best way to compare last row with new insert

Hi !
for MS SQL 2000

I need an UsersHistory Table where i cannot INSERT 2 rows one after the other with the same user.name

I can get

Bob
David
Bob

but not

Bob
Bob
David

something like an INDEX on rows
or
INSERT INTO UsersHistory (name) VALUES ('bob') IF MAX(name) <> 'bob' ?

what is the best way to do it ?

thank youYou need some other column to order by, say a datetime. it could store when the user last logged in/logged out/whatever. Why? because the physical order of rows in a table has no meaning. Since you are storing a history, the thing you want to order by is a time, so you need a datetime column.

Then you could do something like this:

-- assumes you already have a username in a @.name variable
declare @.time datetime
select @.time = max(LoggedInAt) from UsersHistory

if not exists(select * from UsersHistory where LoggedInAt=@.time and UserName=@.name)
begin
insert into UsersHistory (UserName, LoggedInAt) values (@.name, getdate())
end|||I have allready that datetime column = getdate()

but i dont understand the meaning of your query , if the last user row is Bob the next row cannot be Bob, it doesnt depend on the DateTime it can be 10 minutes ... one year
I must have an history of LastUsers for certains events in the database, the LastUser is the Last one as long as nobody do something and replace the last one (I know my english is terrific ! :-))

the last inserted row is also the MAX(id)

thanks a lot Jezemine|||Do something like:

INSERT INTO UsersHistory (name) VALUES ('bob') IF (SELECT fname from UsersHistory where id = max(id)) <> 'bob'

Note: not actual code