[AccessD] checkbox concatenation

Hi William

Sorry for the incomplete comment.
Of course you can do bitmapping in Access VBA, even in SQL, it is just not very fast as you miss a bitmapped index to search on - that's what Caché (as one example) has.

For some inspiration on SQL code, read up the message "Math problem" of 2003-10-15:

http://databaseadvisors.com/mailman/htdig/accessd/2003-October/014778.html 

/gustav 


>>> wdhindman at dejpolsystems.com 31-10-2006 21:08 >>>
...oh come on guys! ...first its my dictionary and if I say it grows 
logarithmically then that's what it does, eh.
...geometrically! ...balderdash, I say ...where is Charlotte when we need 
her to maintain discipline? :)

...and then both Gustav and Jim do more than hint that good old Access isn't 
up to bit mapping this :(

...and of course Stuart takes a gratuitous swing at my joins ...see above 
...its MY join, eh!

...sheesh ...if this were the old AccessD ...long before daddyhood mellowed 
the hell out of JC, I'd just have him Colbyize the lot of you!

...and here I am, still as dazed and confused as when I first posted 
...early Alzheimer's anyone?

...thanks :)

William Hindman
----- Original Message ----- 
From: "Jim Lawrence" <accessd at shaw.ca>
To: "'Access Developers discussion and problem solving'" 
<accessd at databaseadvisors.com>
Sent: Tuesday, October 31, 2006 1:46 PM
Subject: Re: [AccessD] checkbox concatenation


...and a further comment:

If the table was growing *logarithmically*, William would be delighted!  The
problem is that it is growing *geometrically*.

Reading the Cache doc, a bitmap index may just do the trick, especially as
the max number of events is probably not that large.
Since this is a sparse array problem, it may also work well with an R-tree
(as found in PostgreSQL).

Jim

-----Original Message-----
From: accessd-bounces at databaseadvisors.com 
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Gustav Brock
Sent: Tuesday, October 31, 2006 9:10 AM
To: accessd at databaseadvisors.com 
Subject: Re: [AccessD] checkbox concatenation

Hi William

That would require an engine capable of bit-mapped indexing and searching.
At least one can do this, InterSystems Caché:

http://www.intersystems.com/cache/ 

http://www.intersystems.com/cache/technology/components/bitmap/index.html 

/gustav

>>> wdhindman at dejpolsystems.com 31-10-2006 15:47:51 >>>
...given four tables

   tblContact pk ContactID fk CompanyId
   tblCompany pk CompanyID
   tbEvent pk EventID
   tblEventReg pkERID fk EventID fk CompanyD fk ContactID

...tblEventRegistration is a join table to show which contacts from which
companies attended which events.
...given that thousands of contacts attend each event, tblEventReg is
growing logarithmically

Q: is it feasible to use a numeric field in the tblContacts to replace
tblEventReg by using event checkboxes instead, assigning them a numeric
value by show and then mathematically summing them in the numeric field
...thus using one integer to represent every event attended by that contact?

...yes/no? ...pros/cons?

William Hindman