Help with Microsoft Access Bill-of-material forms

[David]

I have a bill-of-material structure for recipes and when I try to build new
recipes I cannot enter data in some of the fields on the subform. The recipe
information is on the main part of the form and my subform has the
ingredients. The existing ingredients show up but I cannot add new ones
because it won't let me fill in the fields.

Any help would be appreciated.

David

 

[Evi]

A bill-of-Material database structure (if we are thinking of the same thing)
is a very complex database structure often used for documenting machinary
where a machine is made up of smaller machines which are made up of smaller
units, right down to the individual cogs and washers. It involves all sorts
of scary self-joins.and tables are often updated with code in unbound forms
rather than with the regular form with subform.. Why do you use it for
something simple like recipes? It's like learning how to fly a jumbo jet so
that you can get some milk from your corner shop.


Evi

 

[Fred]

Evi is right about BOM's. I've implemented BOM's in Access for our
company's engineering and manufacturing operations. Including a few
simplifications to make the task manageable.

Expanding on what EVI said, while recipies could be considered a "Bill of
Material", and indeed use a core building block of BOM implementations (a
one-to-many relationship), in their usual use they are fundamentally
different. First, and entry (like "1/4 of flour") is really handled as a
text string. In a manufacturing environment, you'd set a part number up for
flour, define it's units of measure (e.g. "cups") , and them, when using it
in a BOM, specify the part number of the flour and the quantity.

Secondly, real life recipies can be handled by a single level BOM structure
(two levels of tables.). The few exceptions of multi-level BOM's that one
could come up with are unnecessary.

The core of your structure could be just two joined tables.

tblFinalFood Main Fields: FinalFoodNum (autonumber PK) and
FinalFoodDescription

tblIngredients Main Fields FinalFoodNum (that it's used in) and
IngredientDescription (example entry: "1/4 cup of flour)


I suspect that you may have already done something like this and have a
simpler problem, that your record source (e.g. a joined query or joind tables
for the form) may be uneditable. There's a lot written on this, but a
simple idea is to make sure that the record source only involves 2 tables)
and that the linked field on the "one" side of the relationship is set as a
primary key.