John,

Thanks...actually I did originally define both fields as the primary key.

Basically, what I have is an invoice table, an invoice-source junction
table, and a source table. What I found was that when I added more than one
source to an invoice, I would get the error message. As you suggested, I do
have a a form
based on the "invoice" table, and a subform based on the invoice-source
junction
table. Here is the SQL query on which the form-subform is based:

SELECT jnct_Invoice_Source.Invoice_ID, jnct_Invoice_Source.Source_ID,
jnct_Invoice_Source.Amount, Source.Source_Name,
jnct_Invoice_Source.Initial_Source, jnct_Invoice_Source.Init_Source_Repaid,
jnct_Invoice_Source.jnct_Invoice_Source_ID
FROM Source INNER JOIN (Invoices INNER JOIN jnct_Invoice_Source ON
Invoices.Invoice_ID = jnct_Invoice_Source.Invoice_ID) ON Source.Source_ID =
jnct_Invoice_Source.Source_ID;

Thanks again for your help.





"John W. Vinson" wrote:

On Tue, 13 Apr 2010 17:46:01 -0700, boooney
wrote:

I have read that "in a junction table, you need to set the primary key to
include the primary key fields from the other two tables. "

Well, it's a good idea, but it's not in fact obligatory.

If I do this, I keep getting the error message "the change you requested to
the table were not successful because they would create duplicate values in
the index, primary key, or relationship.

Sounds like you defined just one of the fields as the primary key, rather than
ctrl-clicking both fields and clicking the Key icon. Both foreign keys should
have the key icon next to them in table design view - not just one of them.

The only way I'm entering data is through a form based on a query which
automatically writes to all 3 tables (the junction and 2 parents) at once.

Generally a Very Bad Idea. Why not use the tools that Access provides - a form
based on one of the "one" side tables, and a subform based on the junction
table?

If I remove the primary keys in the junction tables, I no longer get the
error message. Am I going to regret this later?

Junction tables, plural? Are there more than one?

--

John W. Vinson [MVP]
.