Joins & Cascading

  • Thread starter Thread starter Kelli
  • Start date Start date
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Kelli

I am relatively new to Access, and am currently creating a new Database, four
tables, definately obeying the first two normal forms. The main table (named
tblCO) has a field named Conc# that is designated as the primary key. I need
to join the remaining three tables to tblCO so that when a value is input
into the Conc# field, it cascades to the other three table.
I will ultimately build a form for users to work with in data input/editing,
but am using the tables myself during the developement stage. As I put in
data, I can not get the Conc# field values to propogate to the other tables.
I have joined them and have selected Referential Integrity and Cascade Update
and Cascade Delete.
What might I be doing incorrectly.
Thank you for you interest in my problem
Kelli
 
I would first check my relationships. A one-to-one is where, say, you have
one salesman, one product to sell. In that case, you usually don't need but
one table unless it is huge and then you might split into two. One-to-many
is, say, one salesman, many products. In that case you want the primary key
in the one table to be the foreign (not primary) key in the ohter tables. If
you have many-to-many, say many salesmen, many products, you need tables in
between those tables to connect them together or you won't get good results.
Cascade updates and deletes will only update or delete what is in the
relationship.
 
I am relatively new to Access, and am currently creating a new Database, four
tables, definately obeying the first two normal forms. The main table (named
tblCO) has a field named Conc# that is designated as the primary key. I need
to join the remaining three tables to tblCO so that when a value is input
into the Conc# field, it cascades to the other three table.
Click to expand...

That's not how relationships work! A relationship *prevents* adding invalid
records; it doesn't automagically create a new record.
I will ultimately build a form for users to work with in data input/editing,
but am using the tables myself during the developement stage.
Click to expand...

Use a form with subforms from the start. If you have a child table displayed
in the subform using Conc# as the Master/Child Link Field it will fill in
automatically for you. Table datasheets are for data storage; they are *very
limited* when it comes to data entry.
As I put in
data, I can not get the Conc# field values to propogate to the other tables.
Click to expand...

It won't, and you shouldn't expect it to do so. After all some parent records
might not HAVE any child records; some might have one; some might have
thousands. Create the child record when you have data to put in the child
record (using a Subform); there is no need to create an empty "placeholder"
record.

I have joined them and have selected Referential Integrity and Cascade Update
and Cascade Delete.
Click to expand...

Cascade Update will update an existing linked child record when you change the
value of the primary key field in an existing record in the table (something
that should rarely or never be done, since primary keys should be stable).
What might I be doing incorrectly.
Click to expand...

Just your expectation.
 
John,
That was sage advice.
I lowered my expectations, and got more cool things done than I thought I
could>

Many thanks.
 
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