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. "

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.

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.

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

Thanks.

On Tue, 13 Apr 2010 17:46:01 -0700, boooney
<(E-Mail Removed)> 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]

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
> <(E-Mail Removed)> 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]
> .
>

On Wed, 14 Apr 2010 08:43:02 -0700, boooney
<(E-Mail Removed)> wrote:

>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.

No. Your subform is NOT "based on the invoice-source table". It is based on a
Query joining all three tables. That's why you're having the difficulty!

Change the Form's Recordsource to just the Invoice table - or a query sorting
the invoice table by date, or invoice number, or whatever's convenient; and
change the Subform's Recordsource to just jnct_Invoice_Source. Use InvoiceID
as the master/child link field, and use a combo box based on Source bound to
Source_ID so you can display the source name rather than the ID.

--

John W. Vinson [MVP]