Apologies for the plug but I am just trying to explain.

During development and testing of the LINKWAY ODBC driver we found that many
PC applications, not just Delphi and Powerbuilder seemed to think that the
whole world revolved around 'C' and are of the habit of stripping all
trailing spaces.

For this reason LINKWAY builds up fixed length character fields with
trailing spaces and checks the nullability property of a field before
deciding what to do with a completely empty (but not NULL field).

For those of you who are IMAGE only literate an ALLBASE database carries an
indicator against a NULLABLE field to show if it is NULL or not and it does
get upset f it is supplied with an empty field which is NOT NULL !!
______________________________________________
Ken Vickers
LINKWAY Development and Support
Computing Solutions Limited
10 St Andrews Road
Droitwich, Worcestershire
UNITED KINGDOM
TEL +44 (0) 1905 794400
FAX +44 (0) 1905 794464
http://www.csllink.com
mailto:[log in to unmask] or [log in to unmask]
______________________________________________

-----Original Message-----
From: Bob Walker <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: 24 June 1998 22:59
Subject: Re: Allbase G2.04 and ODBC - Fixed but alas the saga continues


>From:                     Melvin R Rees <[log in to unmask]>
>
>> I have figured out the problem with the ODBC not openning properly and
>> have found my UPDATE problem was not corrected. In case anyone is
>> interested here is what I found out.
>>
>> If you try to change an item on the Allbase database that is NULL,
>> Delphi will tell you that someone else already has changed that record
>> and refuse to touch it.  The log file in ODBCSE indicates this:
>
>Sounds suspiciously like a problem I had with PowerBuilder.
>You may be able to extrapolate to Delphi.
>I was using Image/SQL. Sounds like your using ALLBASE.
>This description may still be useful.
>
>When inserting from PowerBuilder to ImageSQL, sometimes a  NULL
>value would be placed into an Image text field(that is, a binary
>zero would be written into the first character of the text field
>rather than the whole field just being blank).
>
>Subsequent updates to these records would fail with error like:
>'Record changed between read and update'.
>
>What was happening was Image/SQL(or Allbase or ODBC) was
>translating the NULL in Image to a blank when the record was read.
>This blank value was being used in the update phrase which failed
>because the value was actually NULL, thinking it had
>changed from blank to NULL since the record had been read.
>Confusing? Yes.
>
>I seem to recall the problem may have been caused by an incomplete
>original INSERT statement.  ie INSERT into DATABASE.TABLE
>(column1,column3) VALUES ('Col 1 Value','Col 3 Value');
>But what about Column 2? is it a NULL or a blank in this case?
>
>Hope this helps.
>Bob.
>
>
>
>
>--=--=--
>Bob Walker, Computer Centre  --  [log in to unmask]
>Capilano College, North Vancouver, BC, CANADA.
>------
>