[DUG] SQL Update

[Rohit Gupta]

If you are using the table then this could happen.... the table reads 
all values of the row in and overwrites them all.  You need to use 
queries.

Date sent:      	Wed, 20 Jul 2005 14:55:44 +1200
From:           	"Eion McIntosh \(Christchurch\)" <e.mcIntosh at ppcs.co.nz>
To:             	"Delphi List Group" <delphi at ns3.123.co.nz>
Subject:        	[DUG] SQL Update
Send reply to:  	NZ Borland Developers Group - Delphi List <delphi at ns3.123.co.nz>
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Hi 
We have a program which runs each a user starts system we have 
to check whether a program is the background is still running by 
checking through the server active programs list that you can see 
from Task manager. If the program find the background process is 
not running it reset a variable on an SQL table, so that the next user 
that logs in, without knowing, automatically start the program 
running again.
We are having the occasional occurance of more than 1 copy of the 
background process running and have found that this variable that 
is being check is being reset to some process which we can't find 
what it is. A few people believe it is the checking program resetting 
this value when it does not think this process is running, when is 
actually is still running. We have check with SQL logs to find when 
the variable is being reset and have found when it is doing it, but it 
is only reseting one field, where we have the checking program 
update two fields on the record, one being a description, so we 
knew that this program was doing the resetting.
The update of the SQL table is very simple: 
If SQL.Field1 = 1 then 
begin 
 SQL.Edit; 
 SQL.Field1 := 0; 
 SQL.Field2 :-= SQL.Feild2 + ' Reset'; 
 SQL.Post; 
end; 
Does any think or know of any possible reason that if this logic is 
resetting the field1, that is would update field2 at the same time? 
When testing the log showed both fields being updated but running 
live only field1 is begin reset, so this is why I can't see this logic is 
causing our second copy of the background process to start 
running.
Regards 
Eion McIntosh 
PPCS Ltd Regards

Rohit

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