Linked Child Record Losing Parent ID

[Dale H]

All,
I have a multi-user database containing a parent table (Header) and a child
table (Detail) which are linked based on an autonum ID in the Header. Data
entry is performed through a form (Header Form) with a subform (Detail Form).
This set-up has been running without problems for 4 years until now. We enter
the Header or category information in the parent form and then the Detail
information or parts in the child form. The autonum ID in the Header is
assigned to each Detail record entered in the Header. The problem is that for
some reason now, individual Detail records are being kicked out; ie: the ID
number from the Header is being replaced with a 0 (zero). The child records
are being "orphaned" as it seems. The ID is the primary key in the Header
table and there is no primary key in the Detail table. It appears random. We
cannot identify a common action or pick up a pattern which may be causing
this. Can anyone give me some guidance? Any help would be greatly
appreciated. Thank you.

 

[Dale H]

Part 2: Now I'm thinking that this could be a record locking confilct,
however I'm curious as to why it has not occurred in the past. No two
persons are working in the same header at the same time. We currently have 6
people working in the database. We have had up to 10 people working in other
identical databases with no problems. --
dale

 

[KARL DEWEY]

Your Detail records should have number field (integer) that matches the
autonum ID in the Header table. These should be joined in a one-to-many
relationship with referential integrity.