I have three procedures that I need to call in specific order in one procedure. How can I do that?
Lets say that one procedure is called proc_log. Other three procedures that must be called in proc_log are: insert_header, insert_mapping, insert_item (strictly in that order).
Could someone give a code sample on how to do this?
Sure; one after another.
create or replace procedure proc_log is
begin
insert_header;
insert_mapping;
insert_time;
end;
/
You can do this as shown below:
CREATE OR REPLACE PROCEDURE proc_log
AS
BEGIN
BEGIN
insert_header ();
EXCEPTION
WHEN OTHERS THEN
raise_application_error( -20001,'In insert_header' );
END;
BEGIN
insert_mapping ();
EXCEPTION
WHEN OTHERS THEN
raise_application_error(-20002,'In insert_mapping');
END;
BEGIN
insert_item ();
EXCEPTION
WHEN OTHERS THEN
raise_application_error(-20003,'In insert_item');
END;
EXCEPTION
WHEN OTHERS THEN
raise_application_error(-20001,'In proc_log');
END;
Related
I have one requirement in which I have to design two procedure.First procedure will generate one output variable value and then second procedure will use to do its task. I am giving same kind of scenario in below code
create procedure existingProc(
begin
insert statementprogramming statement
);
create procedure MyProc(
begin
call existingProc();
-- Exsisting procedure return some value
-- and this value is used in MyProc
commit;
);
In the above code existingProc is already there in the system and I can not change it. IN the procedure transaction is begin but not committed. This procedure generate one value as Output param and MyProc will used this value.
I want that after executing the existingProc, MyProc procedure should get the value, but it is not happening and it is giving null.
what should i do here, Please help me. I can not share the code that why giving scenario.
Does this help clarify how to use the output parameters from one procedure in another procedure?
create procedure ExistingProc(output1 out number) is
begin
insert into someTable values ('some values')
RETURNING someCol INTO output1;
end;
create procedure MyProc(args ....) is
Result1 number; --output from existingProc
begin
ExistingProc(result1);
-- Use Result1 as needed
Update stuff ...
where id = Resutl1;
commit;
end;
This is a best practice question on error handling through multiple levels of PL/SQL procedures. I've looked at a few other questions to help me out, in particular this one.
Currently, I have a program with Procedure 1, which calls Procedure 2, which calls Procedure 3. I'm trying to perform adequate error handling - but I'd like to output eventually the exact problem back to the application layer. I'm hoping to get some ideas on how I can do this efficiently and clearly.
My current solution method is below, but it seems rather messy to me, with lots of variable declarations. I am very new to PL/SQL (and SQL in general) so I'd appreciate any advice on:
Good error handling techniques when dealing with multiple layers of procedures.
Feeding error messages back up to application layer (in my procedure below, represented by "out_overall_output" variable.
Program Flow: UI -> Proc 1 -> Proc 2 -> Proc 3
Procedure 1:
--One input variable, one output.
in_id VARCHAR2;
out_overall_output VARCHAR2;
...
DECLARE
l_success BOOLEAN;
l_error_output VARCHAR2(100);
BEGIN
Proc2(id, l_success, l_error_output);
IF l_success = FALSE THEN
out_overall_output = l_error_output
END IF
EXCEPTION
WHEN OTHERS THEN
ROLLBACK;
out_overall_output:= 'Error calling Proc 2'
RETURN;
END;
--Normal flow continues if l_success is true...
Procedure 2:
-- One input variable, two output.
in_id
out_success
out_error_output
//other logic
DECLARE
l_success BOOLEAN;
l_error_output VARCHAR2(100)
BEGIN
Proc3(id, l_success, l_error_output)
IF l_success = FALSE THEN
out_error_output = l_error_output
END IF
EXCEPTION
WHEN OTHERS
out_error_output = 'Error calling Proc 3'
RETURN;
END;
Procedure 3:
--One input variable, two output.
in_id VARCHAR2;
out_success BOOLEAN;
out_error_message VARCHAR2;
...
BEGIN
DELETE
FROM table
WHERE id = in_id;
EXCEPTION
WHEN NO_DATA_FOUND THEN
out_success = FALSE;
out_error_message = 'Error - No data to delete'
WHEN OTHERS THEN
out_success = FALSE;
out_error_message = 'Error deleting data.'
END;
Note: The levels of procedure calling goes deeper than this. The snippets I have shown are greatly simplified. The error messages and variable names in my real procedures are more descriptive.
To show exact explanations of "what happens with a server" for application level you can try following. In procedures:
create or replace procedure p1 is
...
exception
when <some_error> then
<do something>
-- re-raise error:
raise_application_error(-20001, 'Client with ID '|| ID || ' has no right to perform action "' || ACTION_NAME || '"', true);
end;
create or replace procedure p2 is
begin
p1;
exception
when <another_error> then
<do something>
-- re-raise error:
raise_application_error(-20002, 'Action "' || ACTION_NAME || '" is not completed', true);
end;
create or replace procedure p3 is
begin
p2;
exception
when <another_error> then
<do something>
-- re-raise error:
raise_application_error(-20003, 'Purchasing of "' || CAR_NAME || '" cancelled', true);
end;
And in top level procedure:
create or replace procedure top_level_procedure is
begin
p1;
exception
when <one_more_error> then
<do something>
raise_application_error(-20004, dbms_utility.format_error_backtrace);
end;
After exception in p1 you will see something like this:
ORA-20003: Purchasing of "Cool red Ferrari" cancelled
ORA-20002: Action "car purchase" is not completed
ORA-20001: Client with ID 123 has no right to perform action "Spent all money of Bill Gates"
Third parameter of procedure raise_application_error with false value cuts all previous error messages. If you will use false value in procedure p3, you will see only one error message with code ORA-20003 in this example.
P. S. Also you can define your own exceptions and use them in WHEN .. THEN clause. Here you find more information and examples: https://docs.oracle.com/cd/B28359_01/appdev.111/b28370/errors.htm#LNPLS00704
P. P. S. How to log. Log procedure:
create or replace procedure log(p_log_message varchar2) is
pragma autonomous_transaction;
begin
insert into log_table(..., log_message) values (..., p_log_message);
commit;
end;
Call log procedure:
when <one_more_error> then
<do something>
log(..., dbms_utility.format_error_backtrace);
raise_application_error(-20004, dbms_utility.format_error_backtrace);
Is it a bad practice to do what the code below does? Will bad things happen to me for writing it?
Edit: this is just an example. I would not use dbms_output for any real error reporting.
CREATE OR REPLACE PACKAGE my_package
AS
PROCEDURE master;
END;
/
CREATE OR REPLACE PACKAGE BODY my_package
AS
my_global_interrupt EXCEPTION;
PROCEDURE my_private_procedure
IS
BEGIN
-- in case some flag is raised, raise exception to stop process and prepare for resume
RAISE my_global_interrupt;
END;
PROCEDURE master
IS
BEGIN
my_private_procedure;
EXCEPTION
WHEN my_global_interrupt THEN
dbms_output.put_line('global interrupt, ');
-- prepare to resume
END;
END;
/
On the contrary globally defined user exceptions is good practice. Consider the following skeleton of a package body.
create or replace package body my_pkg
as
my_x1 exception;
my_x2 exception;
my_x3 exception;
PROCEDURE p1 is
begin
...
exception
when no_data_found then raise my_x1;
end p1;
PROCEDURE p2 is
begin
...
exception
when no_data_found then raise my_x2;
end p2;
PROCEDURE p3 is
begin
...
exception
when no_data_found then raise my_x3;
end p3;
PROCEDURE master is
begin
p1;
p2;
p3;
exception
when my_x1 then do_this;
when my_x2 then do_that;
when my_x3 then do_the_other;
end master;
end my_pkg;
/
The use of globally declared exceptions makes exception handling in the master procedure easier.
Also, bear in mind that sometimes we want to propagate the exception beyond the package, to say a program which calls our publicly declared procedure. We can do that by defining our exceptions in the package spec. This means other proecdures can reference them...
SQL> begin
2 my_pkg.master;
3 exception
4 when my_pkg.my_public_x1
5 then dbms_output.put_line('oh no!');
6 end;
7 /
oh no!
PL/SQL procedure successfully completed.
SQL>
We can also associate such exceptions with specific error numbers, so that they are recognisable even if the calling procedure doesn't explicitly handled them.
SQL> exec my_pkg.master
BEGIN my_pkg.master; END;
*
ERROR at line 1:
ORA-20999:
ORA-06512: at "APC.MY_PKG", line 32
ORA-06512: at line 1
SQL>
That's (slightly) more helpful than the generic ORA-06510 error.
Looks reasonable enough to me, provided you're happy that after the interrupt condition it's OK to resume processing. If you are going to log the interrupt in some way, it's probably better to insert a row into a log table using an autonomous transaction. You won't see anything from DBMS_OUTPUT until the whole procedure finishes. Then you'll see all the DBMS_OUTPUT at once.
After many Google and SO searches, I cannot find a definitive answer to this simple question:
How can I define a procedure inside of another procedure to use?
I know that there are nested blocks and nested procedures, but I haven't seen the exact syntax for what I want. i.e.
create or replace
PROCEDURE TOP_PROCEDURE
(...)
IS
-- nested procedure here?
BEGIN
NULL;
END;
create or replace
PROCEDURE TOP_PROCEDURE
(...)
IS
variable NUMBER;
PROCEDURE nested_procedure (...)
IS
BEGIN
NULL;
END;
PROCEDURE another_nested_procedure (...)
IS
BEGIN
NULL;
END;
BEGIN
NULL;
END;
Local procedures must be declared after anything else (e.g. variables).
Can PL/SQL procedure in Oracle know it's own name?
Let me explain:
CREATE OR REPLACE procedure some_procedure is
v_procedure_name varchar2(32);
begin
v_procedure_name := %%something%%;
end;
After %%something%% executes, variable v_procedure_name should contain 'SOME_PROCEDURE'. It is also OK if it contains object_id of that procedure, so I can look up name in all_objects.
Try:
v_procedure_name := $$PLSQL_UNIT;
There's also $$PLSQL_LINE if you want to know which line number you are on.
If you are pre-10g, you can 'dig' (parse) it out of
dbms_utility.format_call_stack
Procedures/functions in packages can be overloaded (and nested), so the package name/line number is normally better than the name.
In 10g and 11g I use the "owa_util.get_procedure" function. I normally use this in packages as it will also return the name of an internal procedure or function as part of the package name, i.e. (package_name).(procedure name). I use this to provide a generic EXCEPTION template for identifying where an exception occured.
CREATE OR REPLACE procedure some_procedure is
v_procedure_name varchar2(32);
begin
v_procedure_name := owa_util.get_procedure;
end;
CREATE OR REPLACE PACKAGE some_package
AS
FUNCTION v_function_name
RETURN DATE;
END;
/
CREATE OR REPLACE PACKAGE BODY some_package
AS
FUNCTION v_function_name
RETURN DATE
IS
BEGIN
RETURN SYSDATE;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('ERROR IN '||owa_util.get_procedure);
DBMS_OUTPUT.PUT_LINE(SQLERRM);
END;
END;
/
Here's a neat function that takes advantage of REGEXP_SUBSTR.
I've tested it in a package (and it even works if another procedure in the package calls it):
FUNCTION SET_PROC RETURN VARCHAR2 IS
BEGIN
RETURN NVL(REGEXP_SUBSTR(DBMS_UTILITY.FORMAT_CALL_STACK,
'procedure.+\.(.+)\s', 1,1,'i',1), 'UNDEFINED');
END SET_PROC;