Data Validation - By Screen or Field, a survey

Data Validation - By Screen or Field, a survey

Post by Albert E. Wha » Thu, 08 Jun 1995 04:00:00



In the past ten plus years of developing software I have always been
convinced that the application should validate the date after the user
edits the field, or completes the editing on a data object (a collection
of data fields).  In this manner the user can easily correct their
mistake and progress further.  Make sense?

Now I'm involved in a project where the data validation is performed
before writing the data to the database (when the user clicks on the
save button).  I felt awkward when correct mistakes with this method
because if I made more than one, then I was only prompted with the first
mistake.  Any additional mistakes would only be reported after I again
clicked the save button.  :-(

My question is two fold.  Is anyone else performing validation of user
enterable data by storing the constraints in the database?  And can
anyone recommend a simplistic method of validating the fields based on
constraints stored in the database without a rediculous amount of
overhead?   (I would assume that this might include the reading of the
data constraints immediately after activating the data window in
question?  But then what do I know?).

I would gladly summerize the results of the survey and repost them or
make them available for the FAQ.  Thanks in advance for you assistance.


----------------------------------------------------
Sr. Systems & Database Consultant
CTG Metals, Inc.
258 Kappa Drive
Pittsburgh, PA  15238
(412)963-8288 x5206

 
 
 

Data Validation - By Screen or Field, a survey

Post by John Schaf » Sat, 10 Jun 1995 04:00:00




>Subject: Data Validation - By Screen or Field, a survey
>Date: Wed, 07 Jun 1995 02:48:33 GMT
>In the past ten plus years of developing software I have always been
>convinced that the application should validate the date after the user
>edits the field, or completes the editing on a data object (a collection
>of data fields).  In this manner the user can easily correct their
>mistake and progress further.  Make sense?

>Now I'm involved in a project where the data validation is performed
>before writing the data to the database (when the user clicks on the
>save button).  I felt awkward when correct mistakes with this method
>because if I made more than one, then I was only prompted with the first
>mistake.  Any additional mistakes would only be reported after I again
>clicked the save button.  :-(

>My question is two fold.  Is anyone else performing validation of user
>enterable data by storing the constraints in the database?  And can
>anyone recommend a simplistic method of validating the fields based on
>constraints stored in the database without a rediculous amount of
>overhead?   (I would assume that this might include the reading of the
>data constraints immediately after activating the data window in
>question?  But then what do I know?).

>I would gladly summerize the results of the survey and repost them or
>make them available for the FAQ.  Thanks in advance for you assistance.


>----------------------------------------------------
>Sr. Systems & Database Consultant
>CTG Metals, Inc.
>258 Kappa Drive
>Pittsburgh, PA  15238
>(412)963-8288 x5206

You can perform validation in the "modified" event of the column.  However,
if you display an error message, don't use MessageBox; write your own
message window.  MessageBox won't work because the mouse control has been
changed somehow (see MessageBox() function doc in PB 4.0).

The modified event will only fire once, when the column has been changed by
the user.  If the user does not change the erroneous value, then "modified"
does not get triggered again.  So you will either need to blank out the
erroneous value, or check again when the user tries to Save to the
database.

John

 
 
 

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