TaskFlow Exception Handler Behavior

Hi all,
I have a question about taskflow exception handler.
My customer is using method-call exception handler to display error detail as FacesMessage dialog in their taskflow.
And they are now trying to find the way to call exception handler but not to show the dialog in case that some sort of exceptions happen.
To achieve this requirement they delete FacesContext.addMesage() from their exception handler, but when not call addMessage() they always get return code 500 (internal server error).
From the behavior we've got, do we always need to call addMessage() in it to come back to original page?
Regards,
Atsushi

Hi Frank,
Thank you for your reply. Please let me ask you another question.
When method-call error handler is executed it returns an outcome. And the outcome determines the next activity I get to.
My question is whether it is a designed behavior of method-call error handler that when the below two conditions are met I get back to the original error page to see facesMessage dialog.
1. The method-call outcome doesn't match any control flow case
2. addMessage() is called in the method defined at method-call
If any, I'd like to know how to get back the original page after error handler is executed without faces message.
Thanks,
Atsushi

Similar Messages

Bounded Taskflow Exception Handler not working with Page Fragements

I have one bounded - taskflow task-flow-definition
<?xml version="1.0" encoding="windows-1252" ?>
<adfc-config xmlns="http://xmlns.oracle.com/adf/controller" version="1.2">
<task-flow-definition id="task-flow-definition">
 <default-activity>view1</default-activity>
 <managed-bean>
 <managed-bean-name>backing_main</managed-bean-name>
 <managed-bean-class>view.backing.Main</managed-bean-class>
 <managed-bean-scope>pageFlow</managed-bean-scope>
 </managed-bean>
 <managed-bean>
 <managed-bean-name>backing_view1</managed-bean-name>
 <managed-bean-class>view.backing.View1</managed-bean-class>
 <managed-bean-scope>pageFlow</managed-bean-scope>
 </managed-bean>
 <managed-bean>
 <managed-bean-name>backing_view2</managed-bean-name>
 <managed-bean-class>view.backing.View2</managed-bean-class>
 <managed-bean-scope>pageFlow</managed-bean-scope>
 </managed-bean>
 <exception-handler>view2</exception-handler>
 <view id="view1">
 <page>/view1.jsff</page>
 </view>
 <view id="view2">
 <page>/view2.jsff</page>
 </view>
 <use-page-fragments/>
</task-flow-definition>
</adfc-config>view1.jsff contains one command button, which calls one ActionListener
<?xml version='1.0' encoding='windows-1252'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.1"
 xmlns:af="http://xmlns.oracle.com/adf/faces/rich">
<af:commandButton text="commandButton 1" actionListener="#{pageFlowScope.backing_view1.callMyFunction}"
 binding="#{pageFlowScope.backing_view1.commandButton1}"
 id="commandButton1"/>

</jsp:root>view1.java callMyFunction throws an Exception
 public void callMyFunction(ActionEvent event) throws Exception{
 throw new Exception();
 }view2.jsff is an exception handler
<?xml version='1.0' encoding='windows-1252'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.1"
 xmlns:af="http://xmlns.oracle.com/adf/faces/rich">
<af:activeOutputText value="Exception Occured"
 binding="#{pageFlowScope.backing_view2.activeOutputText1}"
 id="activeOutputText1"
 inlineStyle="font-size:xx-large; color:red;"/>

</jsp:root>above taskflow is dragged-drop as a Region in one file main.jspx
<?xml version='1.0' encoding='windows-1252'?>
<jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" version="2.1"
 xmlns:f="http://java.sun.com/jsf/core"
 xmlns:h="http://java.sun.com/jsf/html"
 xmlns:af="http://xmlns.oracle.com/adf/faces/rich">
<jsp:directive.page contentType="text/html;charset=windows-1252"/>
<f:view>
 <af:document binding="#{pageFlowScope.backing_main.document1}"
 id="document1">
 <af:form binding="#{pageFlowScope.backing_main.form1}" id="form1">
 <af:region value="#{bindings.taskflowdefinition1.regionModel}"
 id="taskf1"
 binding="#{pageFlowScope.backing_main.taskf1}"/>
 </af:form>
 </af:document>
</f:view>

</jsp:root>*pressing a commandButton on view1.jsff throws an Exception as expected but does not go to exceptionHandler [view2.jsff]*
However, this does work with Bounded Task-Flow without page fragments , view1.jspx contains one button, calling one method which throws an Exception,
view2.jspx is an Exception Handler, and in this case it redirects to the view2.jspx [error page]
any ideas?
thanks

Hi,
Pretty much. However, you got the event part wrong, which is mostly my fault here. First, let put down some general JSF facts about event handling.
1. http://java.sun.com/javaee/5/docs/api/javax/faces/component/UIComponent.html#queueEvent(javax.faces.event.FacesEvent)
2. So, basically, queuing an event on a component means queuing it on its parent until you reach the UIViewRoot that will really actually queue it. That strategy allows iterating components to intercept event queued on their children to record the row index as well so that the data model can be synchronized correctly during the broadcast phase (see http://java.sun.com/javaee/5/docs/api/javax/faces/component/UIData.html#queueEvent(javax.faces.event.FacesEvent) and http://java.sun.com/javaee/5/docs/api/javax/faces/component/UIData.html#broadcast(javax.faces.event.FacesEvent))
3. Exceptions that aren't handled by the exception handler are thrown during broadcast or various process* methods.
So, the catch component must leverage these facts to intercept events queued on its children (by overriding queueEvent method) wrapping the original event in a custom on that flag the catch component itself as the source of the event. The result will be that the broadcast method of the catch component will be called to handle the event. The broadcast method must then unwrap the event (to get the original event), gets the original source, then call originalSource.broadcast(originalEvent) within a try-catch block.
Does it make any more sense put that way? Note that it's an obscure part of JSF so I cannot make it incredibly simple either.
Regards,
~ Simon

11g ADF TaskFlow Exception Handling in BPM

Hi Guys
BPM 11g
I have a human task that is implemented as an ADF task flow. I would like to be able to throw an exception from the ADF application and have it handled by the BPM process, does anyone know if this is possible or how I would do that?
At the moment I have an ADF error page - I could return an "error" outcome to the process from that but an error is an error and it feels right to show that in the process instead of a normal outcome.
anyone else worked through this?
cheers,
Steve

help yourself with this thread - Re: Exception Handling
it should answer your question

ADF Task Flow Exception Handling

Hi ,
I tried a very simple thing for taskFlow exception handling.
I created a bounded task flow with a page fragment (View1.jsff) and another view which is the TaskFlow ExceptionHandler (error.jsff).
The view1.jsff has a button whose action is bound to the backing bean. In the backingBean method I deliberately do division by 0.
Since this is an unHandled exception, I would have expected the control to come to error.jsff. But, instead I am shown a pop up box with the error message.
Why is the control not getting redirected to error.jsff ?
Thanks.
S.Srivatsa Sivan

Hi Frank , im having the same problem.
I want to handle exceptions that occur while navigating task flows (example: A user navigates to a task flow that he/she does not have view permission)
I tried using a view activity and method activity as the exception handler but none of them works, the exception is still not handles. It does not even navigate to the exception handler on the task flow.
on the view page i have:
<af:panelStretchLayout topHeight="50px" id="psl1">
<f:facet name="top">
<af:panelGroupLayout layout="scroll"
xmlns:af="http://xmlns.oracle.com/adf/faces/rich"
id="pgl1">
Error message:
<af:outputText value="#{controllerContext.currentRootViewPort.exceptionData.message}" id="ot2"/>
</af:panelGroupLayout>
</f:facet>
<f:facet name="center">
<af:outputText value="#{my_exception_Handler.stackTrace}" id="ot1"/>

</f:facet>
</af:panelStretchLayout>
I tried getting the error message and stacktrace from the controllerContext via EL like this "#{controllerContext.currentRootViewPort.exceptionData.message}"
and from the controllerContext class in functions that i have declared in my_exception_Handler class like this
" ControllerContext ctx = ControllerContext.getInstance();
ViewPortContext vCtx = ctx.getCurrentViewPort();
if(vCtx.getExceptionData() != null){
StringWriter stringWriter = new StringWriter();
PrintWriter printWriter = new PrintWriter(stringWriter);
vCtx.getExceptionData().printStackTrace(printWriter);
return stringWriter.toString();"
But all this dont even matter because when the exception occurs on the task flow it does not navigate to the default exception handler.
thanks for your interest and help in advance.
Cyborg_0912

Exception Handling in bounded taskflows - expected behaviour

Hi,
I'm currently reviewing exception handling in bounded task flows and some things does not seems to be very clear for me.
(q1) Does it make sense that a bounded task flow calls a method (via a method activity) defined on the page definition of another page (outside of the BTF) by using a #{data.xxxmyPageDef.myMethodName.execute} EL expression?
(q2) Is is correct to expect the application to execute the method marked as ExceptionHandler in the taskflow, whenever an exception occurs?
(q3) I created 5 different scenarios where I call a service method which throws an exception, from within a page fragment of the BTF.
(q3 – sc1) Call a service method through the binding layer of the current page (by using #{bindings.xxx.execute})
Result: A dialog containing the exception message appears.
This is what I expected. Althought, the exception handler method does not seems to be invoked.(q3 – sc2) Call a service method through a task flow method activity using #{bindings.xxx.execute}
Result: A dialog containing the exception message appears.
This is what I expected. Althought, the exception handler method does not seems to be invoked.(q3 – sc3) Call a service method through a task flow method activity using #{data.myPageFragementPagedef.xxx.execute} (accessing the pageDef of the page fragment)
Result: Nothing happens.
This is not what I expected. Although, the exception handler method does nog seems to be invoked, I expect the ADF Error Handler to create a FacesMessage.(q3 – sc4) Call a service method through a task flow method activity using #{data.myPageContainingThePageFragmentPageDef.xxx.execute} (accessing the page containing the BTF region)
Result: Nothing happens.
This is not what I expected. Although, the exception handler method does nog seems to be invoked, I expect the ADF Error Handler to create a FacesMessage. (q3 – sc5) Call a service method through a task flow method activity using #{data.aPageOutsideTheBTFPageDef.xxx.execute} (accessing a page outside the BTW)
Result: Nothing happens.
This is not what I expected. Although, the exception handler method does nog seems to be invoked, I expect the ADF Error Handler to create a FacesMessage. (q4) How can it be possible that – without an exception handler – exceptions occur when calling method activities, without the exceptions being translated to FacesMessages?
Thanks in advance,
Koen Verhulst
JDeveloper 11.1.1.4

Koen,
+(q1) Does it make sense that a bounded task flow calls a method (via a method activity) defined on the page definition of another page (outside of the BTF) by using a #{data.xxxmyPageDef.myMethodName.execute} EL expression?+
No. Exceptions should be handled locally.
+(q2) Is is correct to expect the application to execute the method marked as ExceptionHandler in the taskflow, whenever an exception occurs?+
Only for exceptions that are before Render Response. The Render Response Phase is not handled in ADFc. So exceptions that occur in managed beans may fall through
+(q3) I created 5 different scenarios where I call a service method which throws an exception, from within a page fragment of the BTF.+
+(q3 – sc1) Call a service method through the binding layer of the current page (by using #{bindings.xxx.execute}) Result: A dialog containing the exception message appears.+
This is what I expected. Althought, the exception handler method does not seems to be invoked.
The binding layer has an error handler you can override in the DataBinings.cpx file
+(q3 – sc2) Call a service method through a task flow method activity using #{bindings.xxx.execute}+
Result: A dialog containing the exception message appears.
This is what I expected. Althought, the exception handler method does not seems to be invoked.
Again, you use the binding layer to invoke the service
+(q3 – sc3) Call a service method through a task flow method activity using #{data.myPageFragementPagedef.xxx.execute} (accessing the pageDef of the page fragment)+
Result: Nothing happens.
This is not what I expected. Although, the exception handler method does nog seems to be invoked, I expect the ADF Error Handler to create a FacesMessage.
Never use such a call. Its bad practice as there is no guarantee the container you reference is active. Always have the method call activity have its own binding defined when accessing a method call activity. I know there are lots of example floating aroundthat you #{data ...} and many are from 10.1.3. This should be avoided alltogether though
+(q3 – sc4) Call a service method through a task flow method activity using #{data.myPageContainingThePageFragmentPageDef.xxx.execute} (accessing the page containing the BTF region)+
Result: Nothing happens.
This is not what I expected. Although, the exception handler method does not seems to be invoked, I expect the ADF Error Handler to create a FacesMessage.
Again, this is not a proper use of the ADF framework.
+(q3 – sc5) Call a service method through a task flow method activity using #{data.aPageOutsideTheBTFPageDef.xxx.execute} (accessing a page outside the BTW)+
Result: Nothing happens. This is not what I expected. Although, the exception handler method does nog seems to be invoked, I expect the ADF Error Handler to create a FacesMessage.
accessing a page outside the BTW (!!!) This should ring a worst practices alarm on your laptop (obviously doesn't do it either)
+(q4) How can it be possible that – without an exception handler – exceptions occur when calling method activities, without the exceptions being translated to FacesMessages?+
Exceptions are not handled in a single place but stacked. The business service raises an exception and passes it to the binding layer if not handled. The binding layer handles the exception and if it can't passes it to ADFc. ADFc can handle this exception if it is not during Render Response.
Bottom line: There is no single point of exception handling. So as a recommendation for best practices
- Catch and handle exceptions as close as possible to their origins
- If things can go wrong, thy will - use try/catch blocks in managed beans
- Use an exception handling activity in all bounded task flows. In the case of task flow call activities being used exceptions can bubble up to the caller. However, this would take users out of their current application context
- Exceptions not handled in ADFc can be intercepted by overriding the application task flow exception handler (used by the exception handler activities). This would give you a chance e.g. to handle issues during Render Response
- Never fight the framework, never bend the framework: Don't use out of scope access to page definitions and resources. Exception handling is not a replacement for bad code practices (sorry for saying this, its not meant to be rude) :-)
Though I don't have a qualified numbers of bugs open for exception handling in ADF between 11.1.1.4 and now (and some that are open), but there are issues reported in this area. If there is something that really feels wrong, please go ahead and file a bug and provide a test case for development to have a look. The Render Response issue, for example is something we are aware of and that is in discussion (afaik knows, there is a change in exception handling in JSF 2 that may have an impact to what we can do in ADFc).
thanks
Frank

Using Exception Handler in an ADF Task Flow

Hi folks.
Today I gave a try on Exception Handling. while i go through the blog.
https://blogs.oracle.com/ADFProgrammers/entry/using_exception_handler_in_an
I cant able to attain the Solution 2: Re-Routing the task flow to display an error page As per the Figure 9 i make it out.
but it is not navigating error.jsff.
Taskflow return is not working i hope. only Exception thrown only happens from method.
anyone help me out. what I'm missing ?
- jdev 11.1.1.6.0

hi,
is there anyone help me out of this issue.

Exception Handling in ADF

Jdeveloper version 11.1.1.5.0
Use Case :
My application has :- 1 Jspx page ( testPage.jspx ) , 1 taskflow ( testExceptionFlow.xml ) , 1 pageFragment ( testOperation.jsff ).
I have employee table dragged as table on testOperation.jsff with 4 buttons :
1. Delete - Executes the VO's Delete action.
2. Commit - AM's commit operation ( through datacontrol )
3. CustomDeleteAndCommit - One method in VOImpl which deletes the currentRow and calls this.getDBTransaction().commit() method.
4. CustomCommitThroughBean - Action listener in beans calls the commit through operation binding.
I have secured my application and create two users in jazn.xml User1 and User2. Now both users are logged in to the application using different browser.
Both users can see employee with empId 100.
User1 selects a employee with empId 100 and clicks Delete button. Further clicks Commit button.
User2 selects the same employee with empId 100 and clicks Delete button. Further he can choose to commit through different options :
a) Commit
b) CustomCommitThroughBean
OR
CustomDeleteAndCommit
Obviously there will be jboException stating that row is already delete. When I am calling it through CustomCommitThroughBean operationBinding.getErrors() has errors, so I don't see error on UI.
I see a couple of posts about different ways of handling Exception :
[Using Exception Handler in an ADF Task Flow | https://blogs.oracle.com/ADFProgrammers/entry/using_exception_handler_in_an]
[Extending the ADF Controller exception handler | https://blogs.oracle.com/jdevotnharvest/entry/extending_the_adf_controller_exception_handler]
[Task Flow Exception Handler | http://adfpractice-fedor.blogspot.com/2011/12/task-flow-exception-handler-you-must.html]
[Exception Handling in adf (Part 1) | http://adfwithejb.blogspot.com/2012/05/exception-handling-in-adf-part-1.html ]
Which method of exception handling is applicable should be chosen ?
I just want to notify user about exception through some custom message and table should get refreshed for further operation.
My observations :
I get an error dialog in case :
Commit & CustomDeleteAndCommit
whereas no default error in case : CustomCommitThroughBean
I have uploaded my application [here | http://dl.dropbox.com/u/70986236/BlogApplication/OperationBindingExecuteErrorApp.zip ] . Want to implement exception handling in this application.
Thanks,
Rajdeep
Edited by: Rajdeep on Jul 26, 2012 9:45 PM

When you invoke an operation programmatically through an ADF OperationBinding, the eventual exception is not thrown to you but it is reported to the BindingContainer and the BindingContainer automatically adds a FacesMessage of ERROR severity to the FacesContext. If you have an <af:messages> tag in your ADF Faces page, this error message should be displayed automatically.
Dimitar

Custom code as an exception handler not working.

Hi,
I worked on Custom Handler for unauthorized access to a taskflow following the link below and it worked. But a special case in this doesn't work.
http://download.oracle.com/docs/cd/E14571_01/web.1111/b31974/taskflows_complex.htm#ADFFD22602
Scenario-1: I have a link that opens an unauthorized taskflow as blank page. I tried the solution of custom handler and am able to display message or display error page --- WORKS FINE
Scenario-2: I have a link that opens an unauthorized taskflow in a pop-up as blank page. The above solution doesn't work. I tried displaying SOPs but nothing gets print --- DOESN'T WORK.
Details:
The custom handler doesn't work with Pop-ups. I have an unauthorized taskflow that gets called inside a pop-up using a link. Being an unauthorized user, I click on the link and it pops-up with a blank page. As per the custom handler it is supposed to display error-page. But it doesn't.
I tried displaying SOPs inside the handleException method and nothing prints. The exception handler is unable to catch the exception. If this use-case throws some exception, my exception handler would have handle it but it doesn't raise any exception.
Is this something issue that I need to discuss with FMW team?
Any workaround for this would be of great help.
Code Sample:
public void handleException(FacesContext facesContext, Throwable throwable,
PhaseId phaseId) throws Throwable {
String errorMessage = throwable.getMessage();
if (errorMessage != null && errorMessage.indexOf("ADFC-0619") > -1) {
setEL("#{sessionScope.errorMessage}",
"You are not authorized to view this page.");
ExternalContext externalContext =
facesContext.getExternalContext();
externalContext.redirect("ErrorPage");
} else {
super.handleException(facesContext, throwable, phaseId);
Thanks
Raza

Hi Frank,
This scenario is not specific to a particular TaskFlow. In General, there are links in some views, that invokes taskflows and a particular user may not have permission to that TaskFlow. In this scenario, I am not sure where I need to define the method or router. And Hence I registered the Custom Exception Handler as a service as per the documentation.
But the logic in documentation doesn't work with Pop-ups.
Thanks
Raza

Fundamental exception handling irritation

Hello experts,
I have come across a very disturbing effect when using a function module capable of asynchronous execution in a try-cleanup-endtry statement. Please have a look at the following simple construct:
TRY.
 do_some_db_update( ).
 start_proc_chain_with_fm( ).
 COMMIT WORK.
CLEANUP.
 ROLLBACK WORK.
ENDTRY.
The method do_some_db_update( ) can raise an exception (when the update statement contained in it somehow fails). The method start_proc_chain_with_fm( ) uses the fm RSPC_API_CHAIN_START to start some process chain, if it returns with return code failed we raise an exception too.
That is, both methods potentially raise exceptions. Obviously we only want to commit the involved DB changes if neither does and we want to roll back things if one of the two raises an exception (before propagating the exception to a caller).
Now, what happens occasionally is that the latter method fails, i.e. it actually raises an exception, however the programm flow executes both, the remaining code in the try-block (i.e. the COMMIT statement) as well as the CLEANUP-branch (i.e. the ROLLBACK statement, which of course has nothing to roll back by then anymore).
Can somebody please shed some light on this, I am very confused. This behavior upsets the very basis of my understanding of how exception handling in try-catch blocks works.
Of course I somehow suspect the function module's "asychronous" capabilities.. but actually I think this must not have an effect on the construction as such.
Regards,
Sebastian

Hi Matt,
thanks for you answer. The exception thrown is indeed my chain_start_failed_ex (my class-based wrapper around/equivalent of the original failed-"exception" returned by the function module). That is, an exception is thrown and the programm flow should definitly continue after the CLEANUP statement. However, this is not always the case.
As for your proposal this could be a work-around for the concret problem. Nevertheless I would very much like to find a general explanation for this "mystery". In principle I think - regardless of what the methods actually do - the effect discribed should never happen..
Regards,
Sebastian

What is the idea behind Render Response and Exception Handling in TF?

Dear All,
While searching for answer for my question, I find it hard to decipher this line.
task flow exception handling doesn't handle any exception that is in Render Response phase
I found this several times in many post like this.
Re: ADF Exception handling (including RENDER RESPNSE PHASE)
and this
Re: Exception Handling in TaskFlow
What's the idea behind exception handling in task flow that is related to JSF/ADF life cycle?
I can't find a resource on why I should know what phase an exception has been thrown?
Sorry if my question might be vague/ignorant to others, but I just would like to know the idea from experts around here. :)
Thanks.
JDEV 11G PS4

Hi,
Render Response is the last lifecycle phase processed during JSF request. The ADF controller has no chance of handling exceptions that occur during this time (example, exception thrown in managed bean) and therefore in its default exception handling implementation ignores this lifecycle phase. As an application developer you don't need to know when an exception is raised. However, if you find that an exception occurs during Render Response and it is not handled by the ADFc declarative exception handler, then you know. You can try and override the framework exception handler as explained here:
https://blogs.oracle.com/jdevotnharvest/entry/extending_the_adf_controller_exception_handler
However, better practice is to use try/catch blocks surrounding e.g. calls in a managed bean that could cause exceptions
Frank

MC.9 and MCY1 and Exception Handling in (Logistics Inf. Sys)LIS

Hi,
I want the 'Valuated Stock Value" greater then or equal to zero (>=) appear in the MC.9 report. I can create 'Exception' in MCY1 but am unable to do so. Once I am in MCY1; I choose 'Requirements' then Key Figure 'Valuated Stock Value' then 'Type of condition' is 'Threshold Val. Anal.' is set to '> 0'. However, the report still displays zero values in MC.9. I don't want to display 'Valuated Stock Value' zero to be displayed on the report. Please help.
Thanks
Naved

Hey Chris,
I got the point for exception handling in weblogic 9.2. We ae using 9.2. It comes up with the concept of shared page flows which means all my unhandled exceptions are thrown to the shared page flow controller. There based on the type of exception, i can forward the request to appropraite page.
Thanks anywyas,
Saurabh

PL/SQL 101 : Exception Handling

Frequently I see questions and issues around the use of Exception/Error Handling in PL/SQL. More often than not the issue comes from the questioners misunderstanding about how PL/SQL is constructed and executed, so I thought I'd write a small article covering the key concepts to give a clear picture of how it all hangs together. (Note: the examples are just showing examples of the exception handling structure, and should not be taken as truly valid code for ways of handling things)
Exception Handling
Contents
1. Understanding Execution Blocks (part 1)
2. Execution of the Execution Block
3. Exceptions
4. Understanding Execution Blocks (part 2)
5. How to continue exection of statements after an exception
6. User defined exceptions
7. Line number of exception
8. Exceptions within code within the exception block
1. Understanding Execution Blocks (part 1)
The first thing that one needs to understand is almost taking us back to the basics of PL/SQL... how a PL/SQL execution block is constructed.
Essentially an execution block is made of 3 sections...
+---------------------------+
| Declaration Section |
+---------------------------+
| Statements Section |
+---------------------------+
| Exception Section |
+---------------------------+
The Declaration section is the part defined between the PROCEDURE/FUNCTION header or the DECLARE keyword (for anonymous blocks) and the BEGIN keyword. (Optional section)
The Statements section is where your code goes and lies between the BEGIN keyword and the EXCEPTION keyword (or END keyword if there is no EXCEPTION section). (Mandatory section)
The Exception section is where any exception handling goes and lies between the EXCEPTION keyword at the END keyword. (Optional section)
Example of an anonymous block...
DECLARE
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
Example of a procedure/function block...
[CREATE OR REPLACE] (PROCEDURE|FUNCTION) <proc or fn name> [(<parameters>)] [RETURN <datatype>] (IS|AS)
.. declarative statements go here ..
BEGIN
.. code statements go here ..
EXCEPTION
.. exception handlers go here ..
END;
(Note: The same can also be done for packages, but let's keep it simple)
2. Execution of the Execution Block
This may seem a simple concept, but it's surprising how many people have issues showing they haven't grasped it. When an Execution block is entered, the declaration section is processed, creating a scope of variables, types , cursors, etc. to be visible to the execution block and then execution enters into the Statements section. Each statment in the statements section is executed in turn and when the execution completes the last statment the execution block is exited back to whatever called it.
3. Exceptions
Exceptions generally happen during the execution of statements in the Statements section. When an exception happens the execution of statements jumps immediately into the exception section. In this section we can specify what exceptions we wish to 'capture' or 'trap' and do one of the two following things...
(Note: The exception section still has access to all the declared items in the declaration section)
3.i) Handle the exception
We do this when we recognise what the exception is (most likely it's something we expect to happen) and we have a means of dealing with it so that our application can continue on.
Example...
(without the exception handler the exception is passed back to the calling code, in this case SQL*Plus)
SQL> ed
Wrote file afiedt.buf
1 declare
2 v_name VARCHAR2(20);
3 begin
4 select ename
5 into v_name
6 from emp
7 where empno = &empno;
8 dbms_output.put_line(v_name);
9* end;
SQL> /
Enter value for empno: 123
old 7: where empno = &empno;
new 7: where empno = 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 4
(with an exception handler, we capture the exception, handle it how we want to, and the calling code is happy that there is no error for it to report)
SQL> ed
Wrote file afiedt.buf
1 declare
2 v_name VARCHAR2(20);
3 begin
4 select ename
5 into v_name
6 from emp
7 where empno = &empno;
8 dbms_output.put_line(v_name);
9 exception
10 when no_data_found then
11 dbms_output.put_line('There is no employee with this employee number.');
12* end;
SQL> /
Enter value for empno: 123
old 7: where empno = &empno;
new 7: where empno = 123;
There is no employee with this employee number.
PL/SQL procedure successfully completed.
3.ii) Raise the exception
We do this when:-
a) we recognise the exception, handle it but still want to let the calling code know that it happened
b) we recognise the exception, wish to log it happened and then let the calling code deal with it
c) we don't recognise the exception and we want the calling code to deal with it
Example of b)
SQL> ed
Wrote file afiedt.buf
1 declare
2 v_name VARCHAR2(20);
3 v_empno NUMBER := &empno;
4 begin
5 select ename
6 into v_name
7 from emp
8 where empno = v_empno;
9 dbms_output.put_line(v_name);
10 EXCEPTION
11 WHEN no_data_found THEN
12 INSERT INTO sql_errors (txt)
13 VALUES ('Search for '||v_empno||' failed.');
14 COMMIT;
15 RAISE;
16* end;
SQL> /
Enter value for empno: 123
old 3: v_empno NUMBER := &empno;
new 3: v_empno NUMBER := 123;
declare
ERROR at line 1:
ORA-01403: no data found
ORA-06512: at line 15
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
Example of c)
SQL> ed
Wrote file afiedt.buf
1 declare
2 v_name VARCHAR2(20);
3 v_empno NUMBER := &empno;
4 begin
5 select ename
6 into v_name
7 from emp
8 where empno = v_empno;
9 dbms_output.put_line(v_name);
10 EXCEPTION
11 WHEN no_data_found THEN
12 INSERT INTO sql_errors (txt)
13 VALUES ('Search for '||v_empno||' failed.');
14 COMMIT;
15 RAISE;
16 WHEN others THEN
17 RAISE;
18* end;
SQL> /
Enter value for empno: 'ABC'
old 3: v_empno NUMBER := &empno;
new 3: v_empno NUMBER := 'ABC';
declare
ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character to number conversion error
ORA-06512: at line 3
SQL> select * from sql_errors;
TXT
Search for 123 failed.
SQL>
As you can see from the sql_errors log table, no log was written so the WHEN others exception was the exception that raised the error to the calling code (SQL*Plus)
4. Understanding Execution Blocks (part 2)
Ok, so now we understand the very basics of an execution block and what happens when an exception happens. Let's take it a step further...
Execution blocks are not just a single simple block in most cases. Often, during our statements section we have a need to call some reusable code and we do that by calling a procedure or function. Effectively this nests the procedure or function's code as another execution block within the current statement section so, in terms of execution, we end up with something like...
+---------------------------------+
| Declaration Section |
+---------------------------------+
| Statements Section |
| . |
| +---------------------------+ |
| | Declaration Section | |
| +---------------------------+ |
| | Statements Section | |
| +---------------------------+ |
| | Exception Section | |
| +---------------------------+ |
| . |
+---------------------------------+
| Exception Section |
+---------------------------------+
Example... (Note: log_trace just writes some text to a table for tracing)
SQL> create or replace procedure a as
2 v_dummy NUMBER := log_trace('Procedure A''s Declaration Section');
3 begin
4 v_dummy := log_trace('Procedure A''s Statement Section');
5 v_dummy := 1/0; -- cause an exception
6 exception
7 when others then
8 v_dummy := log_trace('Procedure A''s Exception Section');
9 raise;
10 end;
11 /
Procedure created.
SQL> create or replace procedure b as
2 v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4 v_dummy := log_trace('Procedure B''s Statement Section');
5 a; -- HERE the execution passes to the declare/statement/exception sections of A
6 exception
7 when others then
8 v_dummy := log_trace('Procedure B''s Exception Section');
9 raise;
10 end;
11 /
Procedure created.
SQL> exec b;
BEGIN b; END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.B", line 9
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Procedure A's Declaration Section
Procedure A's Statement Section
Procedure A's Exception Section
Procedure B's Exception Section
6 rows selected.
SQL>
Likewise, execution blocks can be nested deeper and deeper.
5. How to continue exection of statements after an exception
One of the common questions asked is how to return execution to the statement after the one that created the exception and continue on.
Well, firstly, you can only do this for statements you expect to raise an exception, such as when you want to check if there is no data found in a query.
If you consider what's been shown above you could put any statement you expect to cause an exception inside it's own procedure or function with it's own exception section to handle the exception without raising it back to the calling code. However, the nature of procedures and functions is really to provide a means of re-using code, so if it's a statement you only use once it seems a little silly to go creating individual procedures for these.
Instead, you nest execution blocks directly, to give the same result as shown in the diagram at the start of part 4 of this article.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure b (p_empno IN VARCHAR2) as
2 v_dummy NUMBER := log_trace('Procedure B''s Declaration Section');
3 begin
4 v_dummy := log_trace('Procedure B''s Statement Section');
5 -- Here we start another execution block nested in the first one...
6 declare
7 v_dummy NUMBER := log_trace('Nested Block Declaration Section');
8 begin
9 v_dummy := log_trace('Nested Block Statement Section');
10 select empno
11 into v_dummy
12 from emp
13 where empno = p_empno; -- Note: the parameters and variables from
 parent execution block are available to use!
14 exception
15 when no_data_found then
16 -- This is an exception we can handle so we don't raise it
17 v_dummy := log_trace('No employee was found');
18 v_dummy := log_trace('Nested Block Exception Section - Exception Handled');
19 when others then
20 -- Other exceptions we can't handle so we raise them
21 v_dummy := log_trace('Nested Block Exception Section - Exception Raised');
22 raise;
23 end;
24 -- ...Here endeth the nested execution block
25 -- As the nested block handled it's exception we come back to here...
26 v_dummy := log_trace('Procedure B''s Statement Section Continued');
27 exception
28 when others then
29 -- We'll only get to here if an unhandled exception was raised
30 -- either in the nested block or in procedure b's statement section
31 v_dummy := log_trace('Procedure B''s Exception Section');
32 raise;
33* end;
SQL> /
Procedure created.
SQL> exec b(123);
PL/SQL procedure successfully completed.
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
No employee was found
Nested Block Exception Section - Exception Handled
Procedure B's Statement Section Continued
7 rows selected.
SQL> truncate table code_trace;
Table truncated.
SQL> exec b('ABC');
BEGIN b('ABC'); END;
ERROR at line 1:
ORA-01722: invalid number
ORA-06512: at "SCOTT.B", line 32
ORA-06512: at line 1
SQL> select * from code_trace;
TXT
Procedure B's Declaration Section
Procedure B's Statement Section
Nested Block Declaration Section
Nested Block Statement Section
Nested Block Exception Section - Exception Raised
Procedure B's Exception Section
6 rows selected.
SQL>
You can see from this that, very simply, the code that we expected may have an exception was able to either handle the exception and return to the outer execution block to continue execution, or if an unexpected exception occurred then it was able to be raised up to the outer exception section.
6. User defined exceptions
There are three sorts of 'User Defined' exceptions. There are logical situations (e.g. business logic) where, for example, certain criteria are not met to complete a task, and there are existing Oracle errors that you wish to give a name to in order to capture them in the exception section. The third is raising your own exception messages with our own exception numbers. Let's look at the first one...
Let's say I have tables which detail stock availablility and reorder levels...
SQL> select * from reorder_level;
 ITEM_ID STOCK_LEVEL
 1 20
 2 20
 3 10
 4 2
 5 2
SQL> select * from stock;
 ITEM_ID ITEM_DESC STOCK_LEVEL
 1 Pencils 10
 2 Pens 2
 3 Notepads 25
 4 Stapler 5
 5 Hole Punch 3
SQL>
Now, our Business has told the administrative clerk to check stock levels and re-order anything that is below the re-order level, but not to hold stock of more than 4 times the re-order level for any particular item. As an IT department we've been asked to put together an application that will automatically produce the re-order documents upon the clerks request and, because our company is so tight-ar*ed about money, they don't want to waste any paper with incorrect printouts so we have to ensure the clerk can't order things they shouldn't.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2 cursor cur_stock_reorder is
3 select s.stock_level
4 ,r.stock_level as reorder_level
5 ,(r.stock_level*4) as reorder_limit
6 from stock s join reorder_level r on (s.item_id = r.item_id)
7 where s.item_id = p_item_id;
8 --
9 v_stock cur_stock_reorder%ROWTYPE;
10 begin
11 OPEN cur_stock_reorder;
12 FETCH cur_stock_reorder INTO v_stock;
13 IF cur_stock_reorder%NOTFOUND THEN
14 RAISE no_data_found;
15 END IF;
16 CLOSE cur_stock_reorder;
17 --
18 IF v_stock.stock_level >= v_stock.reorder_level THEN
19 -- Stock is not low enough to warrant an order
20 DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
21 ELSE
22 IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
23 -- Required amount is over-ordering
24 DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
25 ELSE
26 DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
27 -- Here goes our code to print the order
28 END IF;
29 END IF;
30 --
31 exception
32 WHEN no_data_found THEN
33 CLOSE cur_stock_reorder;
34 DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
35* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
Ok, so that code works, but it's a bit messy with all those nested IF statements. Is there a cleaner way perhaps? Wouldn't it be nice if we could set up our own exceptions...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2 cursor cur_stock_reorder is
3 select s.stock_level
4 ,r.stock_level as reorder_level
5 ,(r.stock_level*4) as reorder_limit
6 from stock s join reorder_level r on (s.item_id = r.item_id)
7 where s.item_id = p_item_id;
8 --
9 v_stock cur_stock_reorder%ROWTYPE;
10 --
11 -- Let's declare our own exceptions for business logic...
12 exc_not_warranted EXCEPTION;
13 exc_too_much EXCEPTION;
14 begin
15 OPEN cur_stock_reorder;
16 FETCH cur_stock_reorder INTO v_stock;
17 IF cur_stock_reorder%NOTFOUND THEN
18 RAISE no_data_found;
19 END IF;
20 CLOSE cur_stock_reorder;
21 --
22 IF v_stock.stock_level >= v_stock.reorder_level THEN
23 -- Stock is not low enough to warrant an order
24 RAISE exc_not_warranted;
25 END IF;
26 --
27 IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28 -- Required amount is over-ordering
29 RAISE exc_too_much;
30 END IF;
31 --
32 DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
33 -- Here goes our code to print the order
34 --
35 exception
36 WHEN no_data_found THEN
37 CLOSE cur_stock_reorder;
38 DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
39 WHEN exc_not_warranted THEN
40 DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
41 WHEN exc_too_much THEN
42 DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
43* end;
SQL> /
Procedure created.
SQL> exec re_order(10,100);
Invalid Item ID.
PL/SQL procedure successfully completed.
SQL> exec re_order(3,40);
Stock has not reached re-order level yet!
PL/SQL procedure successfully completed.
SQL> exec re_order(1,100);
Quantity specified is too much. Max for this item: 70
PL/SQL procedure successfully completed.
SQL> exec re_order(2,50);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL>
That's better. And now we don't have to use all those nested IF statements and worry about it accidently getting to code that will print the order out as, once one of our user defined exceptions is raised, execution goes from the Statements section into the Exception section and all handling of errors is done in one place.
Now for the second sort of user defined exception...
A new requirement has come in from the Finance department who want to have details shown on the order that show a re-order 'indicator' based on the formula ((maximum allowed stock - current stock)/re-order quantity), so this needs calculating and passing to the report...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2 cursor cur_stock_reorder is
3 select s.stock_level
4 ,r.stock_level as reorder_level
5 ,(r.stock_level*4) as reorder_limit
6 ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7 from stock s join reorder_level r on (s.item_id = r.item_id)
8 where s.item_id = p_item_id;
9 --
10 v_stock cur_stock_reorder%ROWTYPE;
11 --
12 -- Let's declare our own exceptions for business logic...
13 exc_not_warranted EXCEPTION;
14 exc_too_much EXCEPTION;
15 begin
16 OPEN cur_stock_reorder;
17 FETCH cur_stock_reorder INTO v_stock;
18 IF cur_stock_reorder%NOTFOUND THEN
19 RAISE no_data_found;
20 END IF;
21 CLOSE cur_stock_reorder;
22 --
23 IF v_stock.stock_level >= v_stock.reorder_level THEN
24 -- Stock is not low enough to warrant an order
25 RAISE exc_not_warranted;
26 END IF;
27 --
28 IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
29 -- Required amount is over-ordering
30 RAISE exc_too_much;
31 END IF;
32 --
33 DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
34 -- Here goes our code to print the order, passing the finance_factor
35 --
36 exception
37 WHEN no_data_found THEN
38 CLOSE cur_stock_reorder;
39 DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
40 WHEN exc_not_warranted THEN
41 DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
42 WHEN exc_too_much THEN
43 DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
44* end;
SQL> /
Procedure created.
SQL> exec re_order(2,40);
Order OK. Printing Order...
PL/SQL procedure successfully completed.
SQL> exec re_order(2,0);
BEGIN re_order(2,0); END;
ERROR at line 1:
ORA-01476: divisor is equal to zero
ORA-06512: at "SCOTT.RE_ORDER", line 17
ORA-06512: at line 1
SQL>
Hmm, there's a problem if the person specifies a re-order quantity of zero. It raises an unhandled exception.
Well, we could put a condition/check into our code to make sure the parameter is not zero, but again we would be wrapping our code in an IF statement and not dealing with the exception in the exception handler.
We could do as we did before and just include a simple IF statement to check the value and raise our own user defined exception but, in this instance the error is standard Oracle error (ORA-01476) so we should be able to capture it inside the exception handler anyway... however...
EXCEPTION
WHEN ORA-01476 THEN
... is not valid. What we need is to give this Oracle error a name.
This is done by declaring a user defined exception as we did before and then associating that name with the error number using the PRAGMA EXCEPTION_INIT statement in the declaration section.
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2 cursor cur_stock_reorder is
3 select s.stock_level
4 ,r.stock_level as reorder_level
5 ,(r.stock_level*4) as reorder_limit
6 ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7 from stock s join reorder_level r on (s.item_id = r.item_id)
8 where s.item_id = p_item_id;
9 --
10 v_stock cur_stock_reorder%ROWTYPE;
11 --
12 -- Let's declare our own exceptions for business logic...
13 exc_not_warranted EXCEPTION;
14 exc_too_much EXCEPTION;
15 --
16 exc_zero_quantity EXCEPTION;
17 PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
18 begin
19 OPEN cur_stock_reorder;
20 FETCH cur_stock_reorder INTO v_stock;
21 IF cur_stock_reorder%NOTFOUND THEN
22 RAISE no_data_found;
23 END IF;
24 CLOSE cur_stock_reorder;
25 --
26 IF v_stock.stock_level >= v_stock.reorder_level THEN
27 -- Stock is not low enough to warrant an order
28 RAISE exc_not_warranted;
29 END IF;
30 --
31 IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
32 -- Required amount is over-ordering
33 RAISE exc_too_much;
34 END IF;
35 --
36 DBMS_OUTPUT.PUT_LINE('Order OK. Printing Order...');
37 -- Here goes our code to print the order, passing the finance_factor
38 --
39 exception
40 WHEN exc_zero_quantity THEN
41 DBMS_OUTPUT.PUT_LINE('Quantity of 0 (zero) is invalid.');
42 WHEN no_data_found THEN
43 CLOSE cur_stock_reorder;
44 DBMS_OUTPUT.PUT_LINE('Invalid Item ID.');
45 WHEN exc_not_warranted THEN
46 DBMS_OUTPUT.PUT_LINE('Stock has not reached re-order level yet!');
47 WHEN exc_too_much THEN
48 DBMS_OUTPUT.PUT_LINE('Quantity specified is too much. Max for this item: '
 ||to_char(v_stock.reorder_limit-v_stock.stock_level));
49* end;
SQL> /
Procedure created.
SQL> exec re_order(2,0);
Quantity of 0 (zero) is invalid.
PL/SQL procedure successfully completed.
SQL>
Lastly, let's look at raising our own exceptions with our own exception numbers...
SQL> ed
Wrote file afiedt.buf
1 create or replace procedure re_order(p_item_id NUMBER, p_quantity NUMBER) is
2 cursor cur_stock_reorder is
3 select s.stock_level
4 ,r.stock_level as reorder_level
5 ,(r.stock_level*4) as reorder_limit
6 ,(((r.stock_level*4)-s.stock_level)/p_quantity) as finance_factor
7 from stock s join reorder_level r on (s.item_id = r.item_id)
8 where s.item_id = p_item_id;
9 --
10 v_stock cur_stock_reorder%ROWTYPE;
11 --
12 exc_zero_quantity EXCEPTION;
13 PRAGMA EXCEPTION_INIT(exc_zero_quantity, -1476);
14 begin
15 OPEN cur_stock_reorder;
16 FETCH cur_stock_reorder INTO v_stock;
17 IF cur_stock_reorder%NOTFOUND THEN
18 RAISE no_data_found;
19 END IF;
20 CLOSE cur_stock_reorder;
21 --
22 IF v_stock.stock_level >= v_stock.reorder_level THEN
23 -- Stock is not low enough to warrant an order
24 [b]RAISE_APPLICATION_ERROR(-20000, 'Stock has not reached re-order level yet!');[/b]
25 END IF;
26 --
27 IF v_stock.stock_level + p_quantity > v_stock.reorder_limit THEN
28 -- Required amount is over-ordering
29

its nice article, have put up this one the blog
site,Nah, I don't have time to blog, but if one of the other Ace's/Experts wants to copy it to a blog with reference back to here (and all due credit given ;)) then that's fine by me.
I'd go for a book like "Selected articles by OTN members" or something. Does anybody have a list of links of all those mentioned articles?Just these ones I've bookmarked...
Introduction to regular expressions ... by CD
When your query takes too long ... by Rob van Wijk
How to pipeline a function with a dynamic number of columns? by ascheffer
PL/SQL 101 : Exception Handling by BluShadow

Delete Statement Exception Handling

Hi guys,
I have a problem in my procedure. There are 3 parameters that I am passing into the procedure. I am matching these parameters to those in the table to delete one record at a time.
For example if I would like to delete the record with the values ('900682',3,'29-JUL-2008') as parameters, it deletes the record from the table but then again when I execute it with the same parameters it should show me an error message but it again says 'Deleted the Transcript Request.....' Can you please help me with this?
PROCEDURE p_delete_szptpsr_1 (p_shttran_id IN saturn.shttran.shttran_id%TYPE,
p_shttran_seq_no IN saturn.shttran.shttran_seq_no%TYPE,
p_shttran_request_date IN saturn.shttran.shttran_request_date%TYPE) IS
BEGIN
DELETE FROM saturn.shttran
WHERE shttran.shttran_id = p_shttran_id
and shttran.shttran_seq_no = p_shttran_seq_no
and trunc(shttran_request_date) = trunc(p_shttran_request_date);
DBMS_OUTPUT.PUT_LINE('Deleted the Transcript Request Seq No (' || p_shttran_seq_no || ') of the Student (' || p_shttran_id ||') for the requested date of (' || p_shttran_request_date ||')');
COMMIT;
EXCEPTION WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE('Error: The supplied Notre Dame Student ID = (' || p_shttran_id ||
'), Transcript Request No = (' || p_shttran_seq_no || '), Request Date = (' || p_shttran_request_date || ') was not found.');
END p_delete_szptpsr_1;
Should I have a SELECT statement to use NO_DATA_FOUND ???

A DELETE statement that deletes no rows (just like an UPDATE statement that updates no rows) is not an error to Oracle. Oracle won't throw any exception.
If you want your code to throw an exception, you'll need to write that logic. You could throw a NO_DATA_FOUND exception yourself, i.e.
IF( SQL%ROWCOUNT = 0 )
THEN
RAISE no_data_found;
END IF;If you are just going to catch the exception, though, you could just embed whatever code you would use to handle the exception in your IF statement, i.e.
IF( SQL%ROWCOUNT = 0 )
THEN
<<do something about the exception>>
END IF;In your original code, your exception handler is just a DBMS_OUTPUT statement. That is incredibly dangerous in real production code. You are relying on the fact that the client has enabled output, that the client has allocated a large enough buffer, that the user is going to see the message, and that the procedure will never be called from any piece of code that would ever care if it succeeded or failed. There are vanishingly few situations where those are safe things to rely on.
Justin

Exception handling is not working in GCC compile shared object

Hello,
I am facing very strange issue on Solaris x86_64 platform with C++ code compiled usging gcc.3.4.3.
I have compiled shared object that load into web server process space while initialization. Whenever any exception generate in code base, it is not being caught by exception handler. Even though exception handlers are there. Same code is working fine since long time but on Solaris x86, Sparc arch, Linux platform
With Dbx, I am getting following stack trace.
Stack trace is
dbx: internal error: reference through NULL pointer at line 973 in file symbol.cc
[1] 0x11335(0x1, 0x1, 0x474e5543432b2b00, 0x59cb60, 0xfffffd7fffdff2b0, 0x11335), at 0x11335
---- hidden frames, use 'where -h' to see them all ----
=>[4] __cxa_throw(obj = (nil), tinfo = (nil), dest = (nil), , line 75 in "eh_throw.cc"
[5] OBWebGate_Authent(r = 0xfffffd7fff3fb300), line 86 in "apache.cpp"
[6] ap_run_post_config(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0x444624
[7] main(0x0, 0x0, 0x0, 0x0, 0x0, 0x0), at 0x42c39a
I am using following link options.
Compile option is
/usr/sfw/bin/g++ -c -I/scratch/ashishas/view_storage/build/coreid1014/palantir/apache22/solaris-x86_64/include -m64 -fPIC -D_REENTRANT -Wall -g -o apache.o apache.cpp
Link option is
/usr/sfw/bin/g++ -shared -m64 -o apache.so apache.o -lsocket -lnsl -ldl -lpthread -lthread
At line 86, we are just throwing simple exception which have catch handlers in place. Also we do have catch(...) handler as well.
Surpursing things are..same issue didn't observe if we make it as executable.
Issue only comes if this is shared object loaded on webserver. If this is plain shared object, opened by anyother exe, it works fine.
Can someone help me out. This is completly blocking issue for us. Using Solaris Sun Studio compiler is no option as of now.

shared object that load into web server process space
... same issue didn't observe if we make it as executable.When you "inject" your shared object into some other process a well-being of your exception handling depends on that other process.
Mechanics of x64 stack traversing (unwind) performed when you throw the exception is quite complicated,
particularly involving a "nearly-standartized" Unwind interface (say, Unwind_RaiseException).
When we are talking about g++ on Solaris there are two implementations of unwind interface, one in libc and one in libgcc_s.so.
When you g++-compile the executable you get it directly linked with libgcc_s.so and Unwind stuff resolves into libgccs.
When g++-compiled shared object is loaded into non-g++-compiled executable's process _Unwind calls are most likely already resolved into Solaris libc.
Thats why you might see the difference.
Now, what exactly causes this difference can vary, I can only speculate.
All that would not be a problem if _Unwind interface was completely standartized and properly implemented.
However there are two issues currently:
* gcc (libstdc++ in particular) happens to use additional non-standard _Unwind calls which are not present in Solaris libc
naturally, implementation details of Unwind implementation in libc differs to that of libgccs, so when all the standard _Unwind
routines are resolved into Solaris version and one non-standard _Unwind routine is resolved into gcc version you get a problem
(most likely that is what happens with you)
* libc Unwind sometimes is unable to decipher the code generated by gcc.
However that is likely to happen with modern gcc (say, 4.4+) and not that likely with 3.4.3
Btw, you can check your call frame to see where _Unwind calls come from:
where -h -lIf you indeed stomped on "mixed _Unwind" problem then the only chance for you is to play with linker
so it binds Unwind stuff from your library directly into libgccs.
Not tried it myself though.
regards,
__Fedor.

Exception handling to catch the outcome of a select

Hello,
I want to use exception handling to exit me out of a function module. I want to have one exception for all errors.
For example, if this select statement does not work, how do I finish up this code to make it work.
error type cx_bsx
try
select * from t001 where BUKRS = '!@#$'
catch <not sure what> into INTO error
raise exception error
endtry.
When I use cx_bsx with the catch, nothing happens even though the select statement fails. Basically I want the catch to work in the same manner as this:
if sy-subrc ne 0.
raise error_table_read.
endif.

If this code is in a function module, then why not just use the function module exceptions.
if sy-subrc ne 0.
raise error_table_read.
endif.
What are you gaining by "catching" this exception in the function module. By using the "exceptions" part of the function module, you are passing this exception back to the calling program.
Regards,
Rich Heilman

TaskFlow Exception Handler Behavior

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