Do I need an address table?

C

Christie

in my Access database I have 3 tables so far, People, Company and Group. But
i think I many need an address table. The reason is because I have many
people who are connected to one company and many people connected to many
groups but some people who's address are not attached to a company or group.
How do I avoid having duplicate data?
 
J

Jeff Boyce

Christie

That depends on which entities you wish to keep addresses for.

It sounds like you need to connect a person to an address. But it also
sounds like you don't want to use that person's address (necessarily) when
working with a company or a group. Does that mean a company can have an
address? Can a 'group' have an address?

?!And could more than one person associated with the same company "share"
the company's address (and not have one of their own)?

More info, please...

Jeff Boyce
<Access MVP>
 
C

Christie

Jeff,

Yes, I need to connect a person to an address In most cases, the company
address is a person's only address. We do not have home address and company
address as in our line of business, home addresses are not necessary. And,
many people can work for one company or many people can be in many groups.
 
P

peregenem

Christie said:
I have 3 tables so far, People, Company and Group. But
i think I many need an address table.
Click to expand...

An address is _usually_ an attribute of an entity, rather than being an
entity in its own right. Here's a useful test: if you put addresses
into a separate table, what would you use as a key? If your answer is
to use an autonumber or other such artificial key, then its probably an
attribute and should appears separately in the People, Company tables.
 
P

peregenem

It seems to me that if you will ever have more than one person
at the same address you might as well have an address table!
Click to expand...

I saw a system recently that did this. More than one person shared the
same address and when _one_ of them moved the address row was edited
and so they _all_ had a new address!
This will certainly save time in data entry.
Click to expand...

But does it make sense in the data model? that's the question. For
instance, how do you ensure you don't get duplicate addresses added to
the database? (if you don't have data integrity you don't have anything)
 
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