Stop Access from using wrong identity when appending to linked table on SQL server

Question

TL:DR; version:

If I insert a record into a linked table that has a trigger that inserts a record in a different table, Access displays the global i

Answer 1

An ODBC trace reveals that Access is indeed calling SELECT @@IDENTITY (as opposed to SCOPE_IDENTITY()) after inserting the row into the SQL Server linked table:

Database1       e00-1490    EXIT  SQLExecDirectW  with return code 0 (SQL_SUCCESS)
        HSTMT               0x00000000004D6990
        WCHAR *             0x000000000F314F28 [      -3] "INSERT INTO  "dbo"."Table1"  ("txt") VALUES (?)\ 0"
        SDWORD                    -3

...

Database1       e00-1490    EXIT  SQLExecDirectW  with return code 0 (SQL_SUCCESS)
        HSTMT               0x00000000004D6990
        WCHAR *             0x000007FED7E6EE58 [      -3] "SELECT @@IDENTITY\ 0"
        SDWORD                    -3

Furthermore, this behaviour appears to depend on the ODBC driver being used, since a similar test with MySQL Connector/ODBC shows that Access does not call the corresponding MySQL function LAST_INSERT_ID() after inserting a row into a MySQL linked table.

Given that Access is calling SELECT @@IDENTITY, we must modify our trigger as follows (source: here) to reset the @@IDENTITY value back to its original value

create trigger mytable_insert_trigger on mytable for insert as

declare @identity int
declare @strsql varchar(128)

set @identity=@@identity
--your code
--insert into second table ...
--your code
set @strsql='select identity (int, ' + cast(@identity as varchar(10)) + ',1) as id into #tmp'
execute (@strsql)