In the example below what happens to the lock?
Does it release if the write is not executed?
If not shouldn't you have a RELEASE statement at the end after the last END?

-----Original Message-----
[] On Behalf Of Jon Wells
Sent: Saturday, 9 February 2013 3:57
To: U2 Users List
Subject: Re: [U2] Record locks (Unidata 7.2)

I should add that (in our test account) I switched to the READU statement along 
with a LOCKED clause ->


 I locked one of the records in the list I was processing.  When the program 
was working on that record, the CRT statement was executed, and the program 
moved right along processing the rest of the list; and record I had locked was 
not updated. 

Looking through the 'UniBasic Commands Reference' PDF, I found 'RECORDLOCKED 
(file.var,'.  Perhaps this could be used within a LOOP to control 
things, allowing terminal input where the user can choose what to do about the 
record lock?

I've decided to write the data to a new file, so this is no longer a big issue 
for me.  If I had created the program using our vendor's tool kit, the 
generated code would have added all the appropriate gunk the system uses for 
record locks.  The responses have been interesting as I've been looking for a 
chance to better understand how Unidata shops handle locks.  

Thank you,
Jon Wells

 From: Tony Gravagno <>
Sent: Friday, February 8, 2013 2:30 AM
Subject: Re: [U2] Record locks (Unidata 7.2)
I think people understand exactly what you're saying, but disagree.
Most applications don't use the more rigorous coding for having a Locked clause 
that provides additional information to the user, retries, etc. That's not 
"wrong", it's just not necessary ...
depending on the site.

That said, when we used to have a lot of people in an office and a dumb 
terminal beeping was a recognized message to everyone, it was OK
(generally) to just do the READU. These days with more alternative UIs, 
thick-client, thin-client, web services, mobile, etc, there's no one to hear 
that beep. So for modern development I would agree that you really don't want 
an unconditional lock hanging around, you want a Locked clause with logic to 
rollback the transaction and exit gracefully, perhaps with a message sent to 
the site admin.

The penalty for Not having a Locked clause with a new UI is that the port will 
hang, the UI will receive a timeout (which many clients aren't prepared to 
process), and the DBMS port could be sitting there indefinitely with no one 
aware of the condition. This can cascade to multiple ports until suddenly 
everything grinds to a halt and GUI users around the world are unable to access 
the app. I believe some heads will be nodding here because I hear about this 
happening occasionally.


> From: Wjhonson
> Then you're misunderstanding what I'm saying.

> From: Kevin King 
> +1. Well stated.
> Woodward, Bob wrote: 
> > In an active user session where users are obtaining a lock for a
> > length of time, you're right.  There are lots of times, though,
> > lock intervention is not a benefit.  It all depends on the need of
> > application and many situations where I would highly recommend
> > using the default locking system of READU.

> > From: Wjhonson
> > I wouldn't however *recommend* this approach to locking as the
> > can never tell if their terminal is waiting on a lock, or just
> > in some other odd manner, or perhaps processing a batch of
> >
> > So it's rather a nasty trick to play on the user, to just use
> > without a LOCKED clause

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