Events in Application View

Question

Hi,
Am using Weblogic 6.0 Sp2 and WLAI 2.0.
I was working with DBMS adapter that comes along with WLAI. I created an
Application View and added
2 update events, on the same table, to it. But only 1 event gets registered
with it. What I mean is, as both the
events are on the same table (CUSTOMER_TABLE in this case) and of same type
(UPDATE here), only one
of them is notified of the event.
I was testing both of these events simultaneously on 2 separate browsers
(with sufficient wait time), and only 1 of
them was notified on the event, the other was timed out. I tried with more
than 2 events of same type, and the same thing
happened.
It seems that weblogic is registering only 1 event of each type defined for
the same table.
Like I defined 3 insert events and 4 updated events on the same table (in
the same application view),
and only 1 of each type, i.e. one of insert and one of update, got
registered, and only those are notified,
others just time out.
Is there anything wrong am doing, or is it a bug somewhere ?
Thanks
Amit Chauhan

Answer 1

Hi Chris,
Everything was on 1 machine. Weblogic server as well as all the 3
browsers.
Out of the 3 events, one of them generated the event using an
'updateService' in the application view,
which updated just 1 record. (While testing the event you have the option of
manual or service).
The other 2 events were waiting with sufficient time delay. (running with
manual option of testing the event)
But after the event only 1 of them got notified and all other timed out.
Thanks
Amit
Chris Stead <[email protected]> wrote in message
news:[email protected]...
Amit,
Were you on three different machines, or did you have three browsers onone
machine?
Were you updating different records (customers) or the same record?
Chris
Amit wrote:
Chris,
Its not my requirement, I was just working with and testing the DBMS
adapter that comes along with WLAI.
This is what I did. I created an Application View AV1. I created 3
update
events E1, E2 and E3 in this application view.
All were update events on the same Customer_Table. Again, its not the
requierment, I was just trying out, how these events work.
I tested all these three events simulatenously in 3 differnt browsers.So
they all were waiting for that event to occur. I updated a customer
record, so I was hoping that event notification will come to all the 3
events in the 3 browsers. But only 1 of them got notified, other 3 timed
out.
So I was just wondering, is it the correct behaviour of events or isthere
something wrong ?
Hope am a bit clear.
Thanks
Amit
Chris Stead <[email protected]> wrote in message
news:[email protected]...
Amit,
Please explain what you are hoping to accomplish with creating 3
events of
the
same event type. The application view sees an insert on theCustomer_Table as
one event, even if it is defined three times.
When a customer get inserted into the Customer_Table, from the EIS'perspective,
that is one event. We can define several business rules based on that
one
event
and don't need to define the event three times. But, maybe I am
missing
something, please let us know why you have approached it this way.Thanks.
Cheers,
Chris
Amit wrote:
Thanks Mitch.
Can you please also explain the behaviour, in case of 1 Application
View
AV1
having 3 events E1, E2 and E3 all
related to Customer_Table insert evetns. According to what you told,
it
will
create 1 insert trigger on customer_table
for all the 3 events. So when the a customer record will be insertedinto
the table, then it will generate 1 event and will
pass on to the event router, and then event router should route this
to
all
the 3 listeners.
But whats actually happening is, the event router, delivers the
event
notification to only 1 of the 3 events.
You can try this on the DBMS adapter that comes along with ADK.
I was using WLAI 2.0
Thanks
Amit
Amit Chauhan
eTouch System
510-795-4800 ext 113
Mitch Upton <[email protected]> wrote in message
news:[email protected]...
Amit,
In general, you can only have one trigger of a given type on a
table.
Some
databases support multiple 'insert' triggers, but some don't.
As your original problem, you can have multiple application viewsagainst
the same
database instance (same server in the case of MSSQL) and each can
have
multiple
events that are named differently, but refer to the same table and
trigger
type
(e.g. insert, update, delete). The event router elliminates
duplicate
table/trigger combinations and sends the unique list to the eventgenerator. The
router DOES remember all event types, and will deliver events to
all
subscribers
regardless if they were the 'first' to request a table/triggercombination.
For example, I can have 2 app views AV1, and AV2, where AV1
defines E1
to
be
related to Customer_Table insert events, and E2 to be related toCustomer_Table
insert events. The event generator attached to the database
instance
will
see only
E1's subscription, and install a trigger on Customer_Table for
insert.
>>>>>
When I insert a record into Customer_Table, the generator willgenerate a
SINGLE
event, and deliver it to the router. The router will deliver TWO
events,
one to
AV1 (as E1 event type), and one to AV2 (as E2 event type).
Deleting AV1.E1 will NOT cause the generator to delete the insert
trigger
on
Customer_Table. It will remain until someone deletes AV2.E2.
I hope this helps...
Mitch
Amit wrote:
Thanks Steven,
Is this a restriction from ADK coz this is not a restriction
from
database. I think, in database, you can have n number oftriggers
of one type on one table. Like there can be 5 update triggers on
customer_table.
Thanks
Amit
Steven Donovan <[email protected]> wrote:
Amit,
I am not sure if you can have multiple events of the same
type on the same table. The database itself can only have
one trigger on the table for an update and/or one for an
insert. However, with a single event, I was able to get
both browsers notified of the event by using the test feature
for one in manual mode (this will cause it to simply wait for
the specified time listening for events) and testing the other
with a service that generated an event. You will have to
start the manual one first for this.
Hope this helps,
Steven Donovan
Amit wrote:
Hi,
Am using Weblogic 6.0 Sp2 and WLAI 2.0.
I was working with DBMS adapter that comes along with WLAI. I
created
an
Application View and added
2 update events, on the same table, to it. But only 1 event
gets
registered
with it. What I mean is, as both the
events are on the same table (CUSTOMER_TABLE in this case)
and of
same
type
(UPDATE here), only one
of them is notified of the event.
I was testing both of these events simultaneously on 2
separate
browsers
(with sufficient wait time), and only 1 of
them was notified on the event, the other was timed out. I
tried
with
more
than 2 events of same type, and the same thing
happened.
It seems that weblogic is registering only 1 event of each
type
defined
for
the same table.
Like I defined 3 insert events and 4 updated events on the
same
table
(in
the same application view),
and only 1 of each type, i.e. one of insert and one of
update,
got
registered, and only those are notified,
others just time out.
Is there anything wrong am doing, or is it a bug somewhere ?
Thanks
Amit Chauhan--
Mitch Upton
Architect - Application Integration
BEA Systems
Denver, 5th Floor
[email protected]
[phone]