Android Question A) 'b4A Client' accessibility to a 'Database Server[via JRDC2]' at i) Network Level ii) at Database level B) Updating B4A Clients from Server - reg.

[beelze69]

Hi !

This is regarding 'b4A clients' accessing a database 'via JRDC2'.

My doubts:
1) Detecting Database Server accessibility at the Network Level -> When the 'B4a Client' comes up, and there is no 'network accessibility' to the 'Server Database [accessed via JRDC2], an appropriate message has to be shown in the 'b4A Client' application that the 'Server Database cannot be reached due to network unavailability/network restrictions' . Here assume that JRDC2 is running on the Server successfully but the 'b4A Client' is not able to access the Database 'due to some 'Network Issues [it may be network unavailability/network restrictions' .

2) Detecting Whether JRDC2 is running or otherwise [at the Client Side] - How to detect in the B4A Client application whether the JRDC2 Server is down or running ? When the b4A client comes up and if the JRDC2 Server is down then an appropriate message has to be shown on the screen. JRDC2 Code shows 'at server side' that the JRDC2 Server is running or otherwise .. How to detect the same in the Client ?

3) Detecting 'all active B4A front-end clients' from the JRDC2 Server and 'updating their front-ends with some information' when that information changes on the Database server - Is it possible to 'update the front-ends' of ALL 'Active b4A clients(at a given point of time)' with 'some information' the moment some data (stored in an RDBMS) is updated on the Server database (on which JRDC2 is running).. Here assume that only the front-end GUI has to be updated and we are not talking of any Local Database Store updation on the b4A Clients.

Is this possible via any code from the Server side ?

Thanks..

 

[Marvel]

1. You can check if a HTTP job is successful, if it is not successful then there is probably no internet connection. You can also return error messages from the server with the handler and just check for the response on the client.
2. I don't know about this.
3. The problem with updating all clients from the server is that some clients might not be online and that means those clients will likely miss the update except you have a way of queuing failed updates. What you can do is check for updates whenever the app is opened or at specific intervals

 

[beelze69]

JRDC2 is running on the Server bu

1. You can check if a HTTP job is successful, if it is not successful then there is probably no internet connection. You can also return error messages from the server with the handler and just check for the response on the client.
2. I don't know about this.
3. The problem with updating all clients from the server is that some clients might not be online and that means those clients will likely miss the update except you have a way of queuing failed updates. What you can do is check for updates whenever the app is opened or at specific intervals

Hi Marvel,

Thanks.. I will check out the HTTP thing.. Regarding 3) I am talking only about 'Front-end GUI' updation and am okay with it (just whoever comes in should be made aware) but I want to know whether 'it is possible to execute such a code from the Server Side' and if yes how it can be done .. Thanks ...