Board index » cppbuilder » Porting application containing IBEventAlerter to BCB6

2005-04-21 02:54:22 AM
cppbuilder112
I am porting the Interbase application from BCB1 to BCB6. Application
contains many BCB1 Data Access and Data Controls VCs. It also uses
IBEventAlerter. IBEventAlerter is the problem, because this VC moved to the
InterBase group, IBEvents in BCB6. It requires now another way of connection
to interbase. Does anybody know the portable solution? Any help is highly
appreciated.
 

"Anatoli M. Dounaevski" < XXXX@XXXXX.COM >wrote:
coded and executed in a very specific way (I recall it being
one of the last things that I learned about IBX).
The most important concept to understand is that the IBEvent
is performed on the server side and the response to the event
is performed on the client side. IOW, the database executes
code in response to an event and your application responds to
what ever the database might tell it to do as a result of the
event. That means that you have to program the database (the
server) as well as your application (the client).
To program the server, you need to add a stored proc to the
database (which you later link into your application using a
TIBStoredProc). The stored proc is added to the database by
using SQL. There is a utility that allows you to run a script
file (.sql) against the database (I don't know the name ...
you have to find it).
The script file should look like:
/* CONNECT TO THE DATABASE */
CONNECT 'C:\SomeThing\SomeThingElse.gdb' USER 'User name' PASSWORD 'a password' ;
/* Create Procedure */
SET TERM !! ;
CREATE PROCEDURE Event_Alert (Event VARCHAR(20)) AS
BEGIN
POST_EVENT :Event;
END !!
SET TERM ; !!
/***************************************/
/* Commit the work so far so that */
/* the GRANT will see the PROCS */
/* */
/***************************************/
COMMIT;
/* Allow others to execute the proc */
GRANT EXECUTE ON PROCEDURE Event_Alert TO PUBLIC;
To explain the above, Event_Alert is the name of the
stored proc. It takes, as input, a string (named Event)
of 20 max characters that is passed to the built-in
database function POST_EVENT. POST_EVENT will pass that
string to every user connected to the database. This
string becomes the EventName parameter for the TIBEvent
OnEventAlert event. This string is how you know what
has happened.
To raise the event, you simply execute the stored proc
when appropriate. For example, if you want to tell the
users that you are going to power down, you would execute
the proc using a string like 'PowerDown'. Then all clients
get IBEvent::OnEventAlert with a string of 'PowerDown'.
Before you execute the stored proc, you have to set the
string (Event parameter):
TIBStoredProc1->ParamByName("Event")->AsString = "PowerDown";
TIBStoredProc1->ExecProc();
Don't forget to call TIBEvent::Register/UnRegisterEvents.
~ JD
 

Thanks a lot for the reply. However, my problem is different. Of course, I
implemented both the triggers on the sever and the client C++ code. I belive
I did not make myself clear. The problem is in the client C++ code when
porting it to BCB6. In the BCB1 I have to say (for simplicity I give the
run-time example)
TIBEventAlerter* ibEvent1 = new TIBEventAlerter; // construct the
alerter
ibEvent1->Database = <ptr to TDatabase object>; // connect to the
database using BDE
ibEvent1->Events->Add( "eventName1"); // add event
names...
ibEvent1->Events->Add( "eventName2");
.....
ibEvent1->Registered = true; //
register the interest
In BCB6:
IBEvents* ibEvent6 = new TIBEvents; // construct
the alerter
ibEvent6->Database = <ptr to TIBDatabase object>; // connect to the
database. THIS LINE IS NOT PORTABLE
ibEvent6->Events->Add( "eventName1"); // add event
names...
ibEvent6->Events->Add( "eventName2");
.....
ibEvent6->Registered = true; //
register the interest
In order to connect the alerter to the database, TDatabase object is used in
BCB1. In BCB6, TIBEvents must connect to the database via TIBDatabase. This
is the problem when porting the legacy code. VCs of these two groups (BDE
and Interbase specific) cannot be combined in the code, and the legacy code
uses, of course, BDE approach (TDatabase, TSession, TTable, TQuery, etc),
because previously BDE was the only way to connect to database (ODBC is too
slow). Currently, BCB6 has also the Interbase specific interface:
TIBDatabase, TIBTransaction, TIBTable, TIBQuery, etc. When porting I cannot
connect TIBEvents to the TDatabase; instead I have to connect it to
TIBDatabase. Thus, I have to use the BCB6 TIBeverything instead of
Teverything in BCB1, and this is the huge job, because, for example, TQuery
to TIBQuery are very different.
Does anybody know how to connect TIBEvents to TDatabase or use BCB1
TIBEventAlerter (or its modifications) in BCB6 in order to connect it to
TDatabase? Otherwise, each application has to have one more connection
(TIBDatabase) exclusively for the TIBEvents. The system I am porting
consists of about 10 applications....Too many extra connections to the
database...
Thanks, everybody.
"JD" < XXXX@XXXXX.COM >wrote in message

{smallsort}

"Anatoli M. Dounaevski" < XXXX@XXXXX.COM >wrote:
My first thought was solve the problem through casting
but a quick check of the hierarchy wasn't helpful.
I suspect that you'll need to convert the db. Firebird
(SourceForge.net) is an open source clone of IBX (well
it started that way but has diverged a bit since then).
However, it's reported to work well with the TIBComponents.
I would suggest that you post to the InterBase group first.
Jeff Overcash, the author of IB, monitors that group so if
there is a way, he'll be able to tell you how to do it.
~ JD