Thanks again. So far your tables line up with what I was
thinking of doing. I'm thinking now that the TEST fields
could just be in tblLot instead of a separate table
because they are characteristics of LotID such as
ElectricalPerformance, AvgParticleSize, etc. ????

-----Original Message-----
Ok. Now we have the following clear description of your
needs:

"The research facility handles ELEMENTS, LOTS, END
PRODUCTS and TESTS. Two
or more ELEMENTS are mixed together, in various amounts
or proportions, into
a LOT. Each LOT is PROCESSED to form an END-PRODUCT.
(There is just one LOT
per END PRODUCT.) The END PRODUCT is then subject to
various TESTS."

Here is the correct table structure to meet those needs
(excluding TESTS).
Obviously your own table & field names may vary from
mine - but there should
be a 1-to-1 correspondence between your tables, and these:

tblElement - one row for each ELEMENT known to the system.
ElementID (PK)
ElementName
- any other attributes of the element as a whole; eg.
toxicity.

tblLot - one row for each LOT known to the system.
LotID (PK)
Processed - a yes/no flag to indicate whether this
LOT has been
processed into an END PRODUCT yet.
- any other attributes of the lot as a whole; eg. date
created.

tblLotElement - one row for each ELEMENT in each LOT.
LotID ( composite )
ElementID ( primary key )
- a field to give the amount or proportion of that
ELEMENT in that LOT.

I haven't included TESTS, because I still do not
understand your description
of those.

Aaron, I hope this helps. Note that I designed the table
structures above,
in about 1 minute (literally), once I understood your
data requirements.
That first "understanding" stage, is where most of the
time lies. Do not
try to design the tables during that stage. The trick is
to get an accurate
understanding of the data requirements, before you start
designing the
tables.

HTH,
TC


"Aaron" wrote in
message
...

-----Original Message (edited w/reply*)-----
Hi AAron

Sorry, but I still don't clearly understand the data
that
you're dealing
with.

Let's get the data descriptions correct, before we
proceed. This may seem
picky, but it is actually the most important step
in "data modelling". A
clear understanding of the data entities must come
first -
then the actual
design of the tables.

Is this correct:

- The research facility handles ELEMENTS, END PRODUCTS,
and PARTS.

- I assume that each ELEMENT has a unique ELEMENTID? If
not, how do you
distinguish different ELEMENTs? *Yes I have a table of
Elements: Autonumber ID and ElementName

- Two or more ELEMENTS are mixed together. The result
is
called a LOT. Each
LOT has a unique LOTID. There is no case where two LOTs
have the same LOTID. *Correct

- Each LOT is PROCESSED to form an END-PRODUCT.

- Is there only one LOT per END PRODUCT, or could you
process several LOTs
into a sinbgle END PRODUCT? *One lot per END PRODUCT

- I assume that each END PRODUCT has an ENDPRODUCTID?
If
not, how do you
distinguish different END PRODUCTs? *The LOTID assigned
at element composition is the same as the ID for the END
PRODUCT. The reason for the different table is because
since it can have more than 1 element and I need to
capture the amount/ratio of each Element used, I thought
it best to have the separate table. If you have another
suggestion please let me know.

- Each END PRODUCT is subject to one or more TESTS.

- I assume that each TEST has a unique TESTID. If not,
how do you
distinguish different TESTSs? *"Tests" are unique
fields
such as ParticleSize, ECvalue, FinalMass. Again, it's
more
of a characterization of the mixture of elements.

- Could one TEST handle several END PRODUCTs
simultaneously? *The Products are tested/characterized
independently but they all receive the same "tests".

Aaron, you may feel I am going backwards with my advice
to you! (We do not
seem to be getting down into the nitty gritty of that
table structures, at
all.) But the reason for this, is that you have not yet
clearly described
the data that you need to manage. So IMO, it is
premature
to comment on the
table structures.

Unfortunately I'll be busy for the next 2 days, & have
little or no time on
the net. But I'm happy to get back to this as soon as I
return. Or maybe
someone else will jump in & help.
Cheers,
TC

*I appreciate the assistance thus far and I understand
you
need to know the data.
--------------------------------------------------------

A research facility mixes elements(LotID),
processes
them,
evaluates the end product and then uses it in a
part
which
will also get tested.

So:
- each part has one (or several?) tests? several
types
of
tests
- each part comprises several end products? The
combined
elements(LotID) can be used in several Part#'s. Each
Part#
uses up to 2 LotID's(Front and Back) but the Front
LotID
is what affects the Part#'s performance.
- each end product comprises several elements? Yes
Correct?



"Aaron" wrote in
message
...

-----Original Message-----

"Aaron" wrote
in
message
...

(snipped)

A research facility mixes elements(LotID),
processes
them,
evaluates the end product and then uses it in a
part
which
will also get tested.

So:
- each part has one (or several?) tests? several
types
of
tests
- each part comprises several end products? The
combined
elements(LotID) can be used in several Part#'s. Each
Part#
uses up to 2 LotID's(Front and Back) but the Front
LotID
is what affects the Part#'s performance.
- each end product comprises several elements? Yes
Correct?


tblComposition (Lot# can be made up of 1-?
elements)
LotID (FK to tblManufacturing)
Element (chemical or metal)
ElementRatio (amount)

What is the primary key of that table? Actually I
have
a
autonumber CompID PK as well as a multi-field index
between LotID and Element.
What does one row in that table, represent?
Row1: Auto#,LotID112233,Al,60
Row2: Auto#,LotID112233,Cu,40
The concatenated result would be
LotID112233,AlCu,60:40



tblManufacturing
LotID (PK)
ProcessEquip
RunDate
%Source
SourceID
What does one row in that table, represent? The
combined
elements from above are mixed with a source element
to
produce the final combination which will be used in a
part.


tblEvaluation (characterization of LotID's
after
mfg)
LotID (PK)one-one relationship to
tblMAnufacturing
ParticleSize
ECValue
FinalMAss

What is the primary key of that table? LotID is
actually
the PK
What does one row in that table,represent? (I don't
understand: "characterization of LotID's after
manufacturing". You need to describe the table in
terms
of
the entitites you
have mentioned so far: parts, tests, elements, end
products, etc.) The combined/processed elements are
tested
(characterized) before being used in Parts. Each row
will
contain the results for a LotID


tblParts
Part# (PK)
LotID (FK to tblManufacturing)
Account
Performance (test data of Part#)

Aaron, that is the only table that is clearly
described
so far. Each row in
that table represents a single, unique Part. Each
part
is
identified by a
unique Part#. Part# is the primary key of that
table.
We
need the same level
of understanding of your other tables, before we can
comment.

HTH,
TC



One of the key deliverables from this database
is
to
provide Evaluation data and Part listings for
every
combination of Elements and %Source
information.
i.e;
LOT#AALL12 had a 10%Source and was made up of
Al,Si,Cu at
a ratio of 60,20,20 and was used in
PART#1234,PART#5678,etc
If I continue down this path I will need to
concatenate
the records in the tblComposition and I don't
know
how big
a problem that will be. I also don't know what
other
problems I am not considering. Please advise.
Thanks.


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