Antw: [SQL] Many booleans

>>> Chris Griffin <cgriffin(at)websales(dot)com> 01.12.1999 04.26 Uhr >>>

> I am working on a DB that keeps information on potential job candidates.
> One of the pieces of information I need to keep is where they are willing to
> relocate. The choices are broken down into 5 regions of the US and northern
> and southern California. There are also choices for the continents plus US
> and world. If the user puts in a search for the US it needs to match any of
> the us regions. If they select any region it needs to match any records with
> US or world selected. Currently I have separate boolean fields for each
> selection. Is there a better way to do this? Thanks.

I'm not sure if I understood your problem, but think you have a hierarchy of regions:
total
|
+-reg1
| |
| +-subreg11
| |
| +-subreg12
|
+-reg2
|
+-subreg21
|
+-subreg22

If you have a candidate looking for a job in reg1, then
a job in subreg11 should match,
a job in subreg12 shoold also match,
a job in subreg21 shoold not match,
....

You have to build a table reglookup
candreg | jobreg
---------------------------
total | subreg11
total | subreg12
total | subreg21
total | subreg22
reg1 | subreg11
reg1 | subreg12
reg2 | subreg21
reg2 | subreg22
subreg11 | subreg11
subreg12 | subreg12
subreg21 | subreg21
subreg22 | subreg22

Now if you are looking for a job in 'reg1', you write
select j.*
from jobs j, reglookup r
where j.region = r.jobreg
and r.candreg = 'reg1';
which gives you all jobs in reg1;

If you have many regions, then the table reglookup can get very large and is not easy to maintain.

I recently wrote a little C-Programm that builds such table, given a much smaller hierarchy table

region | parent
------------------------------
total |
reg1 | total
reg2 | total
subreg11 | reg1
subreg12 | reg1
subreg21 | reg2
subreg22 | reg2

--------------
Gerhard