I wouldn't store the ProductID in the other 2 tables. Instead create a couple of junction tables. See Many-to-Many on how to set this up.

Hi Hezi, a query is non-updateable when the join fields are not primary keys.  ProductT and ManufacturersT are joined by ProductID.  While ProductID is a primary key for ProductT, it is not a primary key for ManufacturersT.  And that is why your query is not updateable.  This is one of the less obvious reasons why some queries are non-updateable.

To solve your problem, you need queries that join primary key fields in order for them to be updateable.

For instance, you may have a ManufacturerProductsT table that contains a list of products for a manufacturer.  This is the kind of junction table Kevin referred to above.  In this case, it is a "child table" for the ManufacturersT table.  It may contain three fields: ManufacturerID, line_number, ProductID -- with the primary key being ManufacturerID and line_number.  Then you join ManufacturersT to ManufacturerProductsT.  The join field will be ManufacturerID, which is a primary key.  And that's how you make this query editable.

The best way to update info is with forms, of course.  For instance, you may want to update ProductID with a combo box lookup on a form, instead of manually typing a product ID into a query.

Thank you ALL for the very interesting solutions.
I need to learn more a bout the many to many relationships and see how its goes.
best regards
hezi