Can you call a PL/SQL procedure from inside a function?
I haven't come across with the practical example.So if anyone has come across with this please share.
Yes. You can call any pl/sql program from inside any other pl/sql program. A function can call a function, a procedure can call a procedure which calls a function, a function can invoke a TYPE BODY...do an INSERT..which causes a TRIGGER to fire.
A simple (not really practical) example.
Using the HR schema where you have an EMPLOYEES table which includes columns EMPLOYEE_ID, FIRST_NAME, and LAST_NAME.
I have a function that takes in an INTEGER which we use to look up an EMPLOYEE record. We take their first and last names, and concat them together, and return the value back in UPPERCASE text.
Before we do that however, we call a procedure which does nothing but take a 5 second nap using the DBMS_LOCK package.
The code:
create or replace procedure do_nothing_comments (x in integer, y in integer)
is
begin
null;
-- yeah, this is a dumb demo
dbms_lock.sleep(5);
end;
/
create or replace FUNCTION upper_name (
x IN INTEGER
) RETURN VARCHAR2 IS
upper_first_and_last VARCHAR2 (256);
BEGIN
SELECT upper (first_name)
|| ' '
|| upper (last_name)
INTO upper_first_and_last
FROM employees
WHERE employee_id = x;
do_nothing_comments (1, 2); -- here we are calling the procedure
RETURN upper_first_and_last;
END;
/
Now let's invoke the function.
DECLARE
X NUMBER;
v_Return VARCHAR2(200);
BEGIN
X := 101;
v_Return := UPPER_NAME(
X => X
);
:v_Return := v_Return;
END;
/
I'm going to do this in SQL Developer using the Execute feature with the function open:
I get the answer back...it just takes 5 seconds longer than it really needed to.
Here you go:
create or replace function demo
return varchar2
as
begin
dbms_output.put_line('Hello');
return 1;
end demo;
Related
i am trying to call a function from stored procedure in Oracle, but not getting any idea how to do.
my function has two IN parameter and one OUT parameter.
in my procedure i am using out sys refcursor . Any refrence or example will help me a lot.
Here is a simple example for calling function inside procedure. Also as mentioned by APC using OUT in function is a bad practice. Instead you can return your required output. And I'm not sure how you are using sys_refcursor, so modify your procedure accordingly
CREATE OR REPLACE FUNCTION SUM_OF_2(NUM1 IN NUMBER,NUM2 IN NUMBER) RETURN NUMBER
IS
RESULT_SUM NUMBER;
BEGIN
RESULT_SUM:=NUM1+NUM2;
RETURN RESULT_SUM;
END;
CREATE OR REPLACE PROCEDURE CALL_FUNCTON(NUM1 NUMBER,NUM2 NUMBER)
AS
V_FINAL_RESULT NUMBER;
BEGIN
V_FINAL_RESULT:=SUM_OF_2(NUM1,NUM2);
DBMS_OUTPUT.PUT_LINE(V_FINAL_RESULT);
END;
BEGIN
CALL_FUNCTON(5,10);
END;
/
CHECK DEMO HERE
Not sure on what your requirement is , maybe you are just trying the code for education purposes. Generally I have not seen much code which uses OUT parameter with functions, in case you want to return multiple values to the caller object then you could use a procedure with more then one OUT variables. There are some limitation on how an oracle function with OUT parameter would differ from a normal function.
CREATE OR REPLACE FUNCTION temp_demo_func(out_var1 OUT NUMBER)
RETURN VARCHAR2 IS
BEGIN
out_var1 := 1;
RETURN 'T';
EXCEPTION
WHEN OTHERS THEN
RETURN 'F';
END temp_demo_func;
/
CREATE OR REPLACE PROCEDURE temp_demo_proc
(
in_var1 NUMBER
,cur_refcur_out OUT SYS_REFCURSOR
) IS
res VARCHAR2(1);
out_var1 NUMBER;
BEGIN
res := temp_demo_func(out_var1 => out_var1);
dbms_output.put_line(out_var1);
OPEN cur_refcur_out FOR
SELECT in_var1
,out_var1
,res
FROM dual;
END;
/
set serveroutput on
declare
cur_refcur_out Sys_Refcursor;
in_var1 number := 22;
begin
temp_demo_proc(in_var1 => in_var1
,cur_refcur_out => cur_refcur_out);
end;
/
Using PL/SQL, it is possible to call a stored function from within that same function. This can be demonstrated with the following example:
CREATE OR REPLACE FUNCTION factorial(x in number)
RETURN number
IS
f number;
BEGIN
IF x = 0 THEN
f := 1;
ELSE
f := x * factorial(x-1);
END IF;
RETURN f;
END;
/
DECLARE
num number;
factorial number;
BEGIN
num := #
factorial := factorial(num);
dbms_output.put_line(' The factorial of '|| num || ' is ' || factorial);
END;
/
Can this be done using PL/SQL stored procedures as well?
Yes, you can write a procedure that calls itself recursively in PL/SQL. Here is an example - implementing the factorial.
With that said, don't ever write a procedure (or a function like yours) without error handling. If you don't understand why, change 5 to 5.3 in the anonymous block below, and you'll see why.
CODE window:
create or replace procedure fact ( x in number, x_fact out number )
as
begin
if x = 0 then x_fact := 1;
else fact(x-1, x_fact);
x_fact := x * x_fact;
end if;
end;
/
set serveroutput on
declare
z number;
begin
fact(5, z);
dbms_output.put_line(z);
end;
/
SCRIPT OUTPUT window (matching each "result" to the corresponding part of the code left as an exercise):
Procedure FACT compiled
PL/SQL procedure successfully completed.
120
You can certainly call PL/SQL functions recursively (with all the usual warnings about the dangers of doing so in any language!).
You are, however, going to run into trouble if you name a local variable the same as your function. You will, for example, get this error when you try to execute the block:
PLS-00222: no function with name 'FACTORIAL' exists in this scope
I have a procedure that has DML commands. the procedure accepts a variable of type out, and it returns a value.
i need call this procedure from a function.
the goal is that the function will return the value of the variable out returns the procedure.
(i need it for SSIS, but I believe that it is useful in other cases.)
During attempts, I got these errors:
ORA-14551: cannot perform a DML operation inside a query tips.
ORA-06519: active autonomous transaction detected and rolled back.
I'm looking for the right syntax to do it.
Example of a solution that works:
The procedure:
create or replace procedure MyProc(outRes OUT NUMBER)
is
begin
update some_table set some_description = 'abc';
commit;
if (some_condition) then
outRes := 666;
else
outRes := 999;
end if;
end MyProc;
Note: You must do commit; at the end of the DML command.
The function:
CREATE or replace FUNCTION MyFunc
RETURN int IS
PRAGMA AUTONOMOUS_TRANSACTION;
myVar number;
begin
MyProc(myVar);
return myVar;
END MyFunc;
Note that at the beginning of the function has: PRAGMA AUTONOMOUS_TRANSACTION;
And this function call:
select MyFunc() as res from dual;
Here is an example of what you need to do. Do know this is UNTESTED, but should give you a general idea of which way to go. This is known as Dynamic SQL and uses bind variables. There's a lot more I don't know such as the data type your procedure spits out and what not... so if it's not varchar2 then change it accordingly...
FUNCTION myFunc(procedure_call varchar2) RETURN VARCHAR2
IS
v_out1 varchar2(500);
BEGIN
EXECUTE IMMEDIATE 'begin '||procedure_call||'( :out1 ); end;' using v_out1;
RETURN v_out;
END;
I have faced this question during an interview very recently. Please hep me on this. Let us say there are two functions in our schema the prototypes of which are as follows,
display(a varchar2, b number)
display(c varchar2, d varchar2, e number)
and I issue the following statement
drop function display;
which function will be dropped?
overloading means use of same subprograms to call different subprograms. this is an example
declare
x number;
y number;
function findenqno (fname1 varchar2) return number is --–function 1
enqno1 number (10);
begin
select enquiryno
into enqno1
from enquiry
where fname = fname1;
return(enqno1);
end;
function findenqno (refcode1 number) return number is --–function 2
enqno1 number (10);
begin
select enquiryno
into enqno1
from enquiry
where refcode = refcode1;
return (enqno1);
end;
begin
-- You call the function as:
X := findenqno ('ANIL');
dbms_output.put_line('using name '||x);
Y := findenqno (1002);
dbms_output.put_line('using refcode '||y);
end;
/
this is not a standlone subprogram so there is no point droping a overloaded function .
as it is not written in the db.
Thought I had followed creation pattern, but the body will not compile. What I am trying to accomplish is to develop a package to run a procedrure periodically to determine at what time and date more than 15 are in use.. Oracle 11g.
The only other data that needs to go into the table beingg inserted into the sysdate.
CREATE OR REPLACE
PACKAGE TAPES_USED AS
function TAPESCOUNT(count number) return number;
procedure INSERT_TAPES_COUNT(sysdate date, count NUMBER);
END TAPES_USED;
/
-----------------------------------------
CREATE OR REPLACE
PACKAGE body TAPES_USED AS
function TAPESCOUNT(count number) return number as count number;
begin
select count(*)
into
count
from DEV.TAPES_IN USE where count(*) > 15;
procedure INSERT_TAPES_COUNT(sysdate date, count NUMBER)as
begin
INSERT INTO DEV.TAPES_USED VALUES
(sysdate, count);
end INSERT_TAPES_COUNT;
END TAPES_USED;
/
Any help or suggestion anyone can offer will be appreciated.
CREATE OR REPLACE
PACKAGE BODY tapes_used AS
FUNCTION tapescount(in_ct NUMBER) RETURN NUMBER IS
ct NUMBER;
BEGIN
SELECT COUNT(*)
INTO ct
FROM dev.tapes_in_use;
IF ct > in_ct THEN
RETURN ct;
ELSE
RETURN NULL;
END IF;
END tapescount;
PROCEDURE insert_tapes_count(sysdt date, ct NUMBER) IS
BEGIN
INSERT INTO dev.tapes_used VALUES (sysdt, ct);
END insert_tapes_count;
END tapes_used;
/
You should refrain from using reserved words such as COUNT and SYSDATE for variable names (I don't know but that could be some of your compilation issues), so I've renamed them. Also, you forgot to END your function. I think you were missing an underscore in your table name in the FROM clause of the SELECT in your function, and you didn't have a RETURN statement in your function, which you must have.
Generally speaking, a function should accept one or more input parameters and return a single value. You're not making use of the input parameter in your function. I've implemented a suggested parameter.
As Egor notes, this isn't a realistic function, and I'm not certain about your intent here. What is the function supposed to do?
Maybe you want your function to return the Date/Time your count was exceeded? You could also combine everything into a single procedure:
PROCEDURE ck_tape_ct(min_tape_ct NUMBER) IS
ct NUMBER;
BEGIN
SELECT COUNT(*)
INTO ct
FROM dev.tapes_in_use;
IF ct > min_tape_ct THEN
INSERT INTO dev.tapes_used VALUES(SYSDATE, ct);
END IF;
END;