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Old April 30th, 2004, 03:17 AM
TC
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Default Will my table design cause future problems

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?

- 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.

- 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?

- I assume that each END PRODUCT has an ENDPRODUCTID? If not, how do you
distinguish different END PRODUCTs?

- 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?

- Could one TEST handle several END PRODUCTs simultaneously?

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


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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