interbase select transaction

[humanista (mruczus)]

Can interbase select transaction (just reading data) fail? Why? I need to
know if I should use a try except for a select.

[Craig Stuntz [TeamB]]

Sure it can fail. You can pass bad SQL, for example, or try to read
something your DB user account doesn't have permission to read.

That said, I don't see why you'd use try/except. Instead, use
try/finally to commit the transaction whether or not the SELECT fails.
There is no need to "roll back" a SELECT, since it doesn't modify data.*

* Selectable stored procs can modify data, but I don't think that's
what you're asking about.

[humanista (mruczus)]

If I do not use a transaction explicitly for a select, is it not commited
and could there be troubles out of that?

[Craig Stuntz [TeamB]]

Post by humanista (mruczus)
If I do not use a transaction explicitly for a select, is it not
commited and could there be troubles out of that?

dbExpress should eventually take care of it for you, but it's a good
idea to use performance monitoring to make sure that is in fact the
case.

[Selmar]

I not use select transaction.
I use:
IF (Query.Transaction.Active = TRUE) THEN
Query.Transaction.Commit;
Query.Active:= FALSE;
Query.SQL.Clear;
Query.SQL.ADD('SELECT * FROM ...');
Query.Active:= TRUE;
IF (Query.Fields.Fields[0].IsNULL = FALSE) THEN
BEGIN

END
ELSE
BEGIN

END;
Query.Active:= false;
Query.SQL.Clear;
Or you can user a transaction in the procedure of the interbase. Hope this
helps.

[Craig Stuntz [TeamB]]

Post by Selmar
I not use select transaction.

Yes you do. You just don't know it. Nothing can be done in IB without
a transaction. Even a SELECT.

[Tiedo Kruisselbrink]

Post by Craig Stuntz [TeamB]

Post by Selmar
I not use select transaction.

Yes you do. You just don't know it. Nothing can be done in IB without
a transaction. Even a SELECT.

Do you mean DBX adds "START TRANSACTION" and "COMMIT" if I don't?
Then I am afraid DBX does this sometimes wrong, when using MS-SQL: I
occasionally get error messages, telling me that I am starting multiple
transactions, when I am sure I don't.

Where can I learn more about this?

Thanks,
Tiedo
--

[Craig Stuntz [TeamB]]

Post by Tiedo Kruisselbrink
Do you mean DBX adds "START TRANSACTION" and "COMMIT" if I don't?

More or less, yes. You can use the TSQLMonitor component to watch the
transactions come and go.