Enforce rules with code or database design?

[noone]

A typical inventory management system would have people linked to items that
link to other items.

However in what I'm trying to do, PCs are one of the inventory items. One PC
can be linked to many monitors and harddisks etc, but only 1 motherboard.

How do I enforce this?

Not every item uses a motherboard, so I didn't put a 'Motherboard' field in
the 'Items' table. Do I create a 'Motherboards' table instead and use a
one-to-one relationship to link to 'Items' table?

If I want to ensure that a PC with AMD cpu can only be linked to a AMD
motherboard and not a Intel board, should I create another table that
contain a list of 'lawful' connections, and use that table as rowsource for
some combox/lisbox?

[Phil Stanton]

Good question

I think??? you can get away with table of Items lets say
ItemID Autonumber Key
ItemDesc Text
Specific Yes/No ' Is this general purpose eg Printer, or
specific eg AMD
NumberLimited Yes/No 'Yes 11 to 1 eg AMD board & CPU, No PC & printer
GroupID

A table of Groups
GroupID
Group eg CPU, Printer, Disk

Then the link table of
ItemID1 Long Number
ItemID2 Long Number

Rules probably enforced by VB
ItemID1 <>ItemID2
If Item1 and Item2 both have Specific set to yes the check names (perhaps
the first few letters of the description are the same)
If Item1 and Item2 both have NumberLimited set to yes then cant have more
than 1 item per group

HTH

Phil
"noone" <no***@nowhere.com> wrote in message
news:br**********@mawar.singnet.com.sg...

A typical inventory management system would have people linked to items that link to other items.

However in what I'm trying to do, PCs are one of the inventory items. One PC can be linked to many monitors and harddisks etc, but only 1 motherboard.

How do I enforce this?

Not every item uses a motherboard, so I didn't put a 'Motherboard' field in the 'Items' table. Do I create a 'Motherboards' table instead and use a
one-to-one relationship to link to 'Items' table?

If I want to ensure that a PC with AMD cpu can only be linked to a AMD
motherboard and not a Intel board, should I create another table that
contain a list of 'lawful' connections, and use that table as rowsource for some combox/lisbox?

[noone]

Thanks Phil, I think your suggestion will work.

"Phil Stanton" <di********@stantonfamily.co.uk> wrote in message
news:3f***********************@mercury.nildram.net ...

Good question

I think??? you can get away with table of Items lets say
ItemID Autonumber Key
ItemDesc Text
Specific Yes/No ' Is this general purpose eg Printer, or
specific eg AMD
NumberLimited Yes/No 'Yes 11 to 1 eg AMD board & CPU, No PC & printer GroupID

A table of Groups
GroupID
Group eg CPU, Printer, Disk

Then the link table of
ItemID1 Long Number
ItemID2 Long Number

Rules probably enforced by VB
ItemID1 <>ItemID2
If Item1 and Item2 both have Specific set to yes the check names (perhaps
the first few letters of the description are the same)
If Item1 and Item2 both have NumberLimited set to yes then cant have more
than 1 item per group

HTH

Phil
"noone" <no***@nowhere.com> wrote in message
news:br**********@mawar.singnet.com.sg...

A typical inventory management system would have people linked to items that

link to other items.

However in what I'm trying to do, PCs are one of the inventory items. One PC

can be linked to many monitors and harddisks etc, but only 1

motherboard.
How do I enforce this?

Not every item uses a motherboard, so I didn't put a 'Motherboard' field

in

the 'Items' table. Do I create a 'Motherboards' table instead and use a
one-to-one relationship to link to 'Items' table?

If I want to ensure that a PC with AMD cpu can only be linked to a AMD
motherboard and not a Intel board, should I create another table that
contain a list of 'lawful' connections, and use that table as rowsource

for

some combox/lisbox?