Re: [firebird-support] Why this returns string truncate??
Em 13/12/2011 09:32, Fabiano escreveu:
I have this situation:
CREATE TABLE TESTE (TXT VARCHAR(100));
insert into TESTE(TXT) values ('MECƒNICA');
This simple select return “Arithmetic overflow or division by zero has
occurred. Arithmetic exception, numeric overflow, or string truncation.
String right truncation.”
select UPPER(TXT) from TESTE
Tested with FB 2.5.1 and 2.5.0.
Why it occurs?
Try to use charset ISO8859_1 or Win_1252
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
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[firebird-support] Multi-Version Consistent Read Question
Hello, I am researching methods to achieve high throughput for a learning chat application I am designing as a self-led student. I came across the Multiversion Control method of ACID and have a theoretical question: though it seems remote that a reader of data wouldn't get an old read what has been the experience and when this occurs what methods are available to alert the read user that data has been updated? Thank you, Joey [Non-text portions of this message have been removed]
Re: [firebird-support] Multi-Version Consistent Read Question
Hello Joey, Can you please tell in what university you are studying? Why you have chosen Firebird - was it some recommendation? Regards, Alexey Kovyazin Hello, I am researching methods to achieve high throughput for a learning chat application I am designing as a self-led student. I came across the Multiversion Control method of ACID and have a theoretical question: though it seems remote that a reader of data wouldn't get an old read what has been the experience and when this occurs what methods are available to alert the read user that data has been updated? Thank you, Joey [Non-text portions of this message have been removed] [Non-text portions of this message have been removed]
RES: [firebird-support] Why this returns string truncate??
I use charset WIN_1252 for Portuguese characters.
-Mensagem original-
De: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] Em nome de Alexandre Benson Smith
Enviada em: terça-feira, 13 de dezembro de 2011 15:06
Para: firebird-support@yahoogroups.com
Assunto: Re: [firebird-support] Why this returns string truncate??
Em 13/12/2011 09:32, Fabiano escreveu:
I have this situation:
CREATE TABLE TESTE (TXT VARCHAR(100));
insert into TESTE(TXT) values ('MECƒNICA');
This simple select return “Arithmetic overflow or division by zero has
occurred. Arithmetic exception, numeric overflow, or string truncation.
String right truncation.”
select UPPER(TXT) from TESTE
Tested with FB 2.5.1 and 2.5.0.
Why it occurs?
Try to use charset ISO8859_1 or Win_1252
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
++
Yahoo! Groups Links
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
++
Yahoo! Groups Links
* To visit your group on the web, go to:
http://groups.yahoo.com/group/firebird-support/
* Your email settings:
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* To change settings online go to:
http://groups.yahoo.com/group/firebird-support/join
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* To change settings via email:
firebird-support-dig...@yahoogroups.com
firebird-support-fullfeatu...@yahoogroups.com
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Re: [firebird-support] Why this returns string truncate??
What's you connection charset ?
You must use the same charset.
see you
Em 13/12/2011 15:33, Fabiano escreveu:
I use charset WIN_1252 for Portuguese characters.
-Mensagem original-
De: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] Em nome de Alexandre Benson Smith
Enviada em: terça-feira, 13 de dezembro de 2011 15:06
Para: firebird-support@yahoogroups.com
Assunto: Re: [firebird-support] Why this returns string truncate??
Em 13/12/2011 09:32, Fabiano escreveu:
I have this situation:
CREATE TABLE TESTE (TXT VARCHAR(100));
insert into TESTE(TXT) values ('MECƒNICA');
This simple select return “Arithmetic overflow or division by zero has
occurred. Arithmetic exception, numeric overflow, or string truncation.
String right truncation.”
select UPPER(TXT) from TESTE
Tested with FB 2.5.1 and 2.5.0.
Why it occurs?
Try to use charset ISO8859_1 or Win_1252
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
++
Yahoo! Groups Links
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
++
Yahoo! Groups Links
++
Visit http://www.firebirdsql.org and click the Resources item
on the main (top) menu. Try Knowledgebase and FAQ links !
Also search the knowledgebases at http://www.ibphoenix.com
++
Yahoo! Groups Links
* To visit your group on the web, go to:
http://groups.yahoo.com/group/firebird-support/
* Your email settings:
Individual Email | Traditional
* To change settings online go to:
http://groups.yahoo.com/group/firebird-support/join
(Yahoo! ID required)
* To change settings via email:
firebird-support-dig...@yahoogroups.com
firebird-support-fullfeatu...@yahoogroups.com
* To unsubscribe from this group, send an email to:
firebird-support-unsubscr...@yahoogroups.com
* Your use of Yahoo! Groups is subject to:
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Re: [firebird-support] Multi-Version Consistent Read Question
At 03:39 AM 14/12/2011, Joey S. wrote: Hello, I am researching methods to achieve high throughput for a learning chat application I am designing as a self-led student. I came across the Multiversion Control method of ACID and have a theoretical question: though it seems remote that a reader of data wouldn't get an old read what has been the experience and when this occurs what methods are available to alert the read user that data has been updated? What the client can see depends on the isolation level of the transaction. At all levels, your client's transaction sees its own changes. Those will not be visible to any other transaction until your client's transaction commits. -- Read Committed allows a client to see any changes committed after his transaction started. It is the responsibility of the client application to re-query the database to bring the remote view up to date. -- Snapshot isolation (a.k.a. concurrency) keeps a persistent view of the database state as it was when your client's transaction started. Your client won't see changes committed by other transactions until his transaction commits. -- Snapshot Table Stability (a.k.a. consistency) is like concurrency, but it also prevents any other transactions from committing work on the tables it is reading. On the other side of the coin, it is difficult for the consistency transaction to get write access to the tables if other transactions already have it. You wouldn't use this level often, if ever. A transaction can *never* see pending writes for other transactions (Dirty Read). However, a pending write by one transaction will always cause a wait (if allowed by the lock resolution policy) or a lock conflict in any others that attempt to change the same rows. How you alert the user to changes is up to you. The methods available vary according to what you are using to wrap the API - some drivers have extreme smarts to detect changes. Commonly, any such methods are based on trapping lock conflict exceptions, the nature of which will depend on both the isolation level and the lock resolution policy (wait/no wait). Another approach is to use the Events mechanism in triggers, whereby an After Insert or Update or Delete trigger will issue a POST_EVENT when a state-changing operation is committed. Clients are set up to listen for these events and you write the application to respond in some appropriate way, e.g., re-query the tables (refresh) in Read Committed; or attempt to commit and refresh in Snapshot/concurrency. ./heLen
