B4J Question B4J - How to subscribe to Firebird 'event' ?

[amorosik]

The Firebird Sql database has a feature that allows the db server to communicate with the clients that have subscribed to the desired events.
It is necessary to create a trigger like:
------------------------------------------
CREATE OR ALTER TRIGGER TR2 FOR PRODUCTS
ACTIVE AFTER UPDATE POSITION 0 AS BEGIN
IF (new.PRICE <> old.PRICE) THEN POST_EVENT 'price_changed';
END
------------------------------------------

https://www.firebirdsql.org/file/documentation/papers_presentations/Power_Firebird_events.pdf

FirebirdSql.Data.FirebirdClient/FbRemoteEventTests.cs at master · cincuranet/FirebirdSql.Data.FirebirdClient

Firebird ADO.NET Data Provider. Contribute to cincuranet/FirebirdSql.Data.FirebirdClient development by creating an account on GitHub.

github.com

This feature is very useful in applications such as chat or similar where the client part must react quickly to changes that occur in the database
It would be very interesting to have this functionality also for B4X programs, and therefore the question is:
how to 'subscribe' a Firebird Sql event from B4X code?

 

[Erel]

I don't think that the jdbc driver supports this feature.

 

[amorosik]

Not via jdbc, but using db driver for dot net (second link) is possible capture the desired events
With this code it is possible to see the lines appear in correspondence of the changes defined in the trigger inside the database:

string ConnectionString = "User=utente;Password=password;DataSource=localhost;Database=c:\pippo.fdb;Charset=NONE;"
FbConnection FbConn = new FbConnection(ConnectionString);
FbConn.Open();
FbRemoteEvent revent = new FbRemoteEvent(FbConn);
FbRemoteEvent remote_event = new FbRemoteEvent(FbConn);
remote_event.AddEvents(new string[] { "Event_Name" });
remote_event.RemoteEventCounts += new FbRemoteEventEventHandler(Evento_Avviato);
remote_event.QueueEvents();
Console.ReadLine();
FbConn.Close();
+
 static void Evento_Avviato(object sender, FbRemoteEventEventArgs args)
 { Console.WriteLine("Event {0} has {1} counts.", args.Name, args.Counts); }

By following this code fragment, is there the possibility to use the driver (Ado Net Firebird data provider), to capture the events defined in the database?

 

[Erel]

It will not work. You can only use JDBC drivers with B4J.

 

[amorosik]

I see now that a jdbc driver is available for Firebird, they call it Jaybird
For Jaybird 4.0, the latest version, extensive documentation is available
Section 8.3 describes how to subscribe to an event present in Firebird, with a code example in section 8.3.1

Jaybird JDBC Driver Java Programmer’s Manual

Could you help me convert the code shown in section 8.3.1 as B4J code?

 

[Erel]

You will need to write a small library for this. It requires some Java knowledge.

 

[amorosik]

I am a super novice, currently I am not able to write a library for B4X environment
But this is extremely important and would allow to have an effective pro-active database, able to react the management procedures to the occurrence of some changes in the data
And therefore I postpone writing the library as soon as possible
As soon as I can understand exactly what it means to 'write a library' I will try to achieve what is described

 

[DonManfred]

But this is extremely important

If it is so important for you and you are not able to write it by yourself then you also can create a Thread in the Job Offer Forum to hire someone who then write the wrapper for you.

 

[amorosik]

If it is so important for you and you are not able to write it by yourself then you also can create a Thread in the Job Offer Forum to hire someone who then write the wrapper for you.

It is an excellent advice
I will definitely keep it in mind

 

[jorge basualdo]

The Firebird Sql database has a feature that allows the db server to communicate with the clients that have subscribed to the desired events.
It is necessary to create a trigger like:
------------------------------------------
CREATE OR ALTER TRIGGER TR2 FOR PRODUCTS
ACTIVE AFTER UPDATE POSITION 0 AS BEGIN
IF (new.PRICE <> old.PRICE) THEN POST_EVENT 'price_changed';
END
------------------------------------------

https://www.firebirdsql.org/file/documentation/papers_presentations/Power_Firebird_events.pdf

FirebirdSql.Data.FirebirdClient/FbRemoteEventTests.cs at master · cincuranet/FirebirdSql.Data.FirebirdClient

Firebird ADO.NET Data Provider. Contribute to cincuranet/FirebirdSql.Data.FirebirdClient development by creating an account on GitHub.

github.com

This feature is very useful in applications such as chat or similar where the client part must react quickly to changes that occur in the database
It would be very interesting to have this functionality also for B4X programs, and therefore the question is:
how to 'subscribe' a Firebird Sql event from B4X code?

Could you resolve it? I need to do almost the same.

 

[amorosik]

Could you resolve it? I need to do almost the same.

No, not yet