Update or Append query to different DB

[tommyg]

Dear All, I have a problem I need to sort out.

I have 3 access db and one Maindb across LAN.
They all have tbl with same properties.

DBmain
1. TblM
Fld1id
Fld2
Fld3
Fld4
Fld5

DB1
2. Tbl1
Fld1id
Fld2
Fld3
Fld4
Fld5

DB2
3.Tbl2
Fld1id
Fld2
Fld3
Fld4
Fld5

DB3
4.Tbl3
Fld1id
Fld2
Fld3
Fld4
Fld5

What do I need to do is update the main table every day but to import only changes into the maindb. Even if I press many times Append or update query it will copy only changes, not duplicates, since there is id field which doesn't allow duplicates.

I already created append query from 1, 2, 3 to update Main tbl but it works only ones (it the maintbl is empty) but if I run it again it will not allow me to due to key which doesn’t allow duplicates.

I guess I need some kind of SQL statement that will specify it but I am not that much advanced, so if you could help me out in this one I would appreciate it very much.

Also if you have any solutions regarding the connection of these three db I would appreciate it very much.

Cheers,
Tommy