get new SQL record ID

Question

How can I get back the autogenerated ID for a new record I just inserted? (Using ASP classic and MSSQL 2005)

Answer 1

SELECT SCOPE_IDENTITY() 

using @@IDENTITY can have unexpected results, so be careful how you use that one. Triggers that insert records to other tables will cause the @@IDENTITY value to change - where SCOPE_IDENTITY() will give you the last identity from only your current scope.

Here's a sample that'll show the difference between @@IDENTITY and SCOPE_INSERT() and how they can return different values..

use tempdb
go
create table table1
    (ID int identity)
go
create table table2
    (ID int identity(100, 1))
go
create trigger temptrig 
    on table1 
    for insert
as
begin

    insert  table2 
     default values;

end
go
insert  table1 
default values;
select  SCOPE_IDENTITY(), 
        @@IDENTITY

Another option that nobody has discussed here is to use the OUTPUT clause that is in SQL 2005. In this case, you'd just have to add the output clause to your insert, and then catch that recordset from your code. This works well when inserting multiple records instead of just 1...

use tempdb
go
create table table1
    (ID int identity)
go
insert   table1 
output   inserted.ID
default values;
--OR...
insert   table1 
output   inserted.$identity
default values;

Answer 2

Where multiple records need to inserted at once in a set-based fashion, it can get more interesting.

I have sometimes used GUIDs generated clientside (but for classic ASP you'd probably need to use a utility to generate the values) or, more often, a NEWSQUENTIALID() constraint on the GUID key column at the server end.

I'm aware not everyone like GIUDS though, for some quite valid reasons (their size and how it affects indexing/paging for one).

http://www.sqlmag.com/Articles/Index.cfm?ArticleID=50164&pg=2