The question of whether to allow empty fields has to do with what you are

interested in tracking in the database. 



Let's say that I'm using a Donor database to track donations, and one field

in the database is called Campaign (to track which fundraising campaign a

donation is connected to). I could make Campaign a required field, with a

value of "not applicable" when a donation is not connected to a particular

campaign.  (Alternatively, entering an empty string--two quote marks with

nothing in between""--can also be used to denote a field that has been

purposely left empty.) Setting it up this way would tell me whether the data

entry person simply didn't know which campaign to choose, or whether the

donation really didn't come from a campaign. If I set it up so that the

field could be left empty, it might be unclear whether the donation was

campaign-related or not. In other words, if you set up the fields as

required, you get more information. 



I would enjoy hearing thoughts from other list members about this topic.



Miriam Engelberg

Technology Faculty/Chief Cartoonist

CompassPoint Nonprofit Services

www.compasspoint.org

(xxx) xxx-xxxx







-----Original Message-----

From: Bob Bedell [mailto:bdbedell@m...]

Sent: Thursday, May 24, 2001 4:25 PM

To: Access

Subject: [access] Nul Values





Hi,



Real basic question about null values. My agency uses this State supplied 

Web application to store client information. Data entry is done through a 

single main form. I've noticed that the designers don't allow any of the 

fields on the form to contain null values before saving the record. We 

must enter either a value, or a code for "not applicable" or a code 

for "no information". Most of the fields in question contain text values. 

So I'm wondering, from an Access application design best practices point 

of few: should one adopt a strategy such as this to avoid null values in 

record fields at all costs? In the Access apps I've designed, I've allowed 

records to contain null fields if that field is irrelevant for a 

particular client. I end up using outer joins in queries a lot though as a 

result. I don't know if this is good or bad or indifferent. Should every 

field in a saved record contain a value, even if it's just an empty 

string, or a 0, or a code for "not applicable" or "no information"?