I am having a bizarre problem that seems very specific to CURSOR FOR Loops inside of a stored procedure. For clarity, I am using Oracle within DBeaver and am attempting to loop over all of the columns in a table and print out the results of a select statement.
I don't have access to the exact code but this is functionally approximate:
CREATE OR REPLACE PROCEDURE column_null(table_name_in IN VARCHAR2)
AS
str_query VARCHAR2(1000);
temp_number NUMBER(10);
CURSOR col_cursor IS
SELECT * FROM user_tab_cols
WHERE table_name = table_name_in;
BEGIN
FOR c_id IN col_cursor
LOOP
str_query := 'select COUNT(*) FROM ' || table_name_in ||
' WHERE ' || c_id.column_name || ' IS NOT NULL';
EXECUTE IMMEDIATE str_query INTO temp_number;
DBMS_OUTPUT.PUT_LINE(temp_number);
END LOOP;
END;
Now, the bizarre part is that if I do this exact same code block outside of a stored function (minus an extra DECLARE keyword), it works as expected. Even if I try to just echo out 'Hello' within a loop it works as expected, but as soon as it becomes a stored procedure it stops working. I've been testing this for hours today, and am completely baffled; for reference, I have only recently become acquainted with PL/SQL so its mysteries escape me.
Furthermore, it seems specific to CURSOR FOR loops; if I replace the Cursor For loop with a generic numeric loop (i.e. FOR c_id IN 1 .. 10), a procedure will produce output just fine. And it isn't just DBMS_OUTPUT.PUT_LINE that's affected; pretty much everything that goes on inside the Cursor For loop is ignored in a stored procedure, including variable updates, even though they work fine otherwise in normal PL/SQL blocks.
To summarize: Works fine as a PL/SQL block, works fine in a numeric for loop, but for some reason the exact combination of stored procedure and cursor for loop causes no output to be produced; in fact from my testing it seems like nothing meaningful happens within the cursor for loop of a stored function.
Is this a DBeaver bug? A PL/SQL oddity? I'm posting here because I'm ignorant as to whether this is expected behavior due to how Procedures and/or Cursor For loops work, or if this is a bug of some kind.
What you have done is declaring a procedure. Now that you have declared it, you have to call it using a program like bellow. Most likely it will generate outputs.
Option 01
set serveroutput on;
Declare
v_table_name_in IN VARCHAR2(499);
Begin
v_table_name_in := 'your table name';
column_null(table_name_in => v_table_name_in);
end;
Option 02
Get a return parameter. ideally a table type as out parameter. and inside the above code, loop through it and print the value.
Option 03.
Log the outputs into a log table.
I found the error was solved by simply adding AUTHID current_user to the procedure; apparently the procedure didn't have permission to access the table it was trying to select. Strangely though, no error was produced when trying to run the procedure; it just didn't produce any output.
Related
So I have a block of PLSQL code that will drop all indexes as shown in the following block of code:
DECLARE
DRP_STMNT VARCHAR2(100) := '';
BEGIN
FOR I IN (SELECT INDEX_NAME FROM USER_INDEXES) LOOP
DRP_STMNT := 'DROP INDEX ' || I.INDEX_NAME;
EXECUTE IMMEDIATE DRP_STMNT;
END LOOP;
END;
/
That will do the job but should I use a cursor instead of embedding my SELECT statement within the FOR LOOP?
Does the FOR LOOP look at the entire table or does it process one row at a time?
What do you guys suggest using and why?
The result will be just the same.
Though, you'll consume some more energy as you'd have to type more characters as you have to declare a cursor and cursor variable, open a cursor, start the loop, fetch from it, take care about exiting the loop, close a cursor.
When you use a cursor FOR loop (as you did), there's much less typing as Oracle does lots of that for you. For free.
I have below query which I am trying to write in a procedure after begin clause. I dont want to use it as a cursor because of some dependency.
I want to make my db link dynamic instead of hardcoding it and for this reason i put my entire for loop in variable. If i take the variable out then my procedure is working fine. I dont want to change logic of my code while trying to make dblink dynamic.
But this part of loop is not working and throwing an error as
encounter the symbol end of the file when expecting one of the following:
PROCEDURE TMP_CHECK
IS
open CS for NESS_QUERY;
loop
fetch CS into REC;
exit when CS%notfound;
INSERT INTO TMP_Data(ID,NAME,ID_TST,CHK_DATE,VALUE,CHECK,SOURCE) VALUES
(IN_SEQ_NO,DB_NAME,DB_ID,REC.DAY_ID,REC.nb_ord,'ORDS','LEOSOFT');
COMMIT;
END LOOP;
CLOSE CS;
END LOOP;
END;
Dynamic SQL is hard because it turns compilation errors into runtime errors. It looks like your query has several compilation errors: duplicate table aliases, out-of-scope alias references, cross joins between the remote tables (unless that is deliberate, in which case yuck!). So the first thing to do is get the query running as straight SQL, only then make it dynamic.
Also don't include commented code in your template SQL. Things are already hard enough, why make them even harder by doing stuff like this?
ORDER BY
-- TE.market asc,
-- TE.entity asc,
TE.dayiid ASC)'
So, now we've got that out of the way let's look at the logic of what you're trying to do. We cannot drop dynamic segments of PL/SQL into a program. This just won't work ...
LQUERY='
FOR REC IN(
SELECT
... because you have not written a complete PL/SQL statement. But there is a way to do what you want: use a cursor variable. We can open a ref cursor for static and dynamic queries. Find out more.
The following is for illustrative purposes only: you haven't explained your business logic, so this is not necessarily the best way of doing things. But it should solve your immediate problem:
declare
....
l_order number;
l_dayiid number;
l_ety_id number;
rc sys_refcursor;
begin
...
FOR IIS_DB IN C_DB
LOOP
IN_DB_LINK:=LEO_DB.DATABASE_LINK;
IN_DAY:=LEO_DB.DAY_ID;
open rc for
'SELECT order,dayiid,ety_id
from ...
ORDER BY TE.dayiid ASC)';
loop
fetch rc into l_order, l_dayiid, l_ety_id;
exit when rc%notfound;
...
end loop;
close rc;
" PLS-00487: Invalid reference to variable 'REC'"
I think your problem is this:
fetch CS into REC;
You have defined REC as a string but clearly it should be a record type, which needs to match the projection of the query you're fetching. So you need to define something like this:
Type rec_t is record (
nb_ord number,
day_id number,
entity number
);
REC rec_t;
Now you can fetch a record into REC and reference its attributes.
Incidentally the nvl() you've written to supply NB_ORD is wrong. The first argument is the one you are testing for null: 500 will never be null so that's what you'll get for every row. You need to swap the parameters round.
I have used os_command.exec to send commands to the Linux shell. I am using Oracle 12c.
Here is an example code which works fine:
select os_command.exec('/home/smucha/app/smucha/product/12.1.0/dbhome_1/bin/sqlldr userid=system/password control=/home/smucha/load_data.cmt')
from dual
I would like to run a similar command in a stored procedure. Is there any way to do this?
I have tried the following but it does not work. My procedure runs without errors but no records are loaded.
execute immediate 'select os_command.exec(''/home/smucha/app/smucha/product/12.1.0/dbhome_1/bin/sqlldr userid=system/acorp56k control=/home/smucha/IZ/load_data.cmt'') from dual';
Your query is never executed. From the documentation:
If dynamic_sql_statement is a SELECT statement, and you omit both into_clause and bulk_collect_into_clause, then execute_immediate_statement never executes.
Your execute immdiate doesn't have an into clause, so it's essentially ignored.
You don't need the query though, you can call the function directly:
procedure foo is
result pls_integer; -- or whatever type your function actually returns
begin
result := os_command.exec('/home/smucha/app/smucha/product/12.1.0/dbhome_1/bin/sqlldr userid=system/password control=/home/smucha/load_data.cmt');
-- do something with the result?
end foo;
As an aside, you might want to consider using an external table rather than a call out to SQL*Loader.
I'm quite new to PL/SQL, and am using Oracle SQL Developer to write a procedure which uses a sequence to generate a primary key for some existing data, to write into another DB.
The code in question is under NDA.. Essentially I have the following:
create or replace
PROCEDURE Generate_Data
(
output IN VARCHAR2
)
AS
-- Variables here --
CURSOR myCursor IS
SELECT data1, data2
FROM table;
CREATE SEQUENCE mySequence <-- error on this line
START WITH 0
INCREMENT BY 1;
BEGIN
LOOP
-- snip --
It raises the error PLS-00103, saying it encountered the symbol CREATE when expecting on of the following: begin, function, package, pragma, procedure, ...
I've been following the example at:
http://www.techonthenet.com/oracle/sequences.php
The reason you're getting this error is that you're trying to perform DDL, in this case creating a sequence, within PL/SQL. It is possible to do this, but you must use execute immediate.
As Alex says, you also wouldn't be able to do this in the declare section. It would look something like this:
begin
execute immediate 'CREATE SEQUENCE mySequence
START WITH 0
INCREMENT BY 1';
end;
However, as Padmarag also says, it's highly unlikely that you want to do this within PL/SQL. It would be more normal to create a sequence outside and then reference this later. More generally speaking, performing DDL inside a PL/SQL block is a bad idea; there should be no need for you to do it.
You don't mention what version of Oracle you're using. From 11g the ways in which you could access sequences got extended. If you're using 11g then you can access the sequence by creating a variable and assigning the next value in the sequence, .nextval, to this variable:
declare
l_seq number;
begin
loop
-- For each loop l_seq will be incremented.
l_seq := mysequence.nextval;
-- snip
end;
If you're before 11g you must (outside of DML) use a select statement in order to get the next value:
declare
l_seq number;
begin
loop
-- For each loop l_seq will be incremented.
select mysequence.nextval into l_seq from dual;
-- snip
end;
Please bear in mind that a sequence is meant to be a persistent object in the database. There is no need to drop and re-create it each time you want to use it. If you were to run your script, then re-run it the sequence would happily keep increasing the returned value.
Further Reading
About sequences
Using sequences
You can't create sequence in the DECLARE block of procedure. Move it after BEGIN. It's arguable if it makes sense, though. You probably need to create it outside your procedure in the first place.
Update
Actually, if you truly want it inside BEGIN/END use following:
EXECUTE IMMEDIATE 'CREATE SEQUENCE mySequence START WITH 0 INCREMENT BY 1';
You'd need to create the sequence before using it.
And in the PL/SQL code use
-- Variables here --1
v_seq_val number;
BEGIN
Select mySequence.nextval from dual into v_seq_val
In general SQL is for DDL(Data Definition Language) and PL/SQL is for DML(Data Manipulation Language) and logic.
If you wanted you could do Create from PL/SQL, but I think that's not what you want over here.
I have a following oracle stored procedure
CREATE OR REPLACE
PROCEDURE getRejectedReasons
(
p_cursor IN OUT SYS_REFCURSOR)
AS
BEGIN
OPEN p_cursor FOR SELECT * FROM reasons_for_rejection;
END;
However, when I run this stored procedure in sql-developer then I dont see anything. I just see something like this:
Connecting to the database oracleLocal.
Process exited.
Disconnecting from the database oracleLocal.
I'm coming from MS sql server and am used to seeing actual results when running a stored procedure like this. Is this stored procedure not returning results because I am using a cursor??
The stored procedure is returning something it's just you aren't doing anything with the results.
You can do this simply by running the following script in SQLDeveloper:
VARIABLE csr REFCURSOR;
EXEC getRejectedReasons(:csr); -- the colon identifies the parameter as a variable
PRINT csr;
Another method is to fetch each row and do some sort of processing:
DECLARE
-- sys_refcursor is weakly typed
refcsr SYS_REFCURSOR;
-- define a record so we can reference the fields
rej_rec Reasons_for_Rejection%ROWTYPE;
BEGIN
getRejectedReasons(refcsr);
-- loop through the results
LOOP
-- gets one row at a time
FETCH refcsr INTO rej_rec;
-- if the fetch doesn't find any more rows exit the loop
EXIT WHEN refcsr%NOTFOUND;
-- Do something here.
-- For example : DBMS_OUTPUT.PUT_LINE(rej_rec.reason_desc);
END LOOP;
END;
You opened the cursor. You didn't select anything from it, update it, or advance it.
All open does, effectively, to select the matching rows into temporary memory, so you can advance the cursor row by row. Which you didn't do.
One of the differences between Oracle and SQL Server is that the latter returns result sets naturally. I'd use a function, by the way.
In Oracle, functions typically return a single element. Cursors came later.
There's some documentation online that will help you understand the use of refcursor bind variables. Here's one such for SQL*Plus:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14357/ch5.htm#sthref1122
I think in SQL Developer you can do the same thing with autoprint on, although I haven't tested that.
Found a blog that also discusses something similar:
http://vadimtropashko.wordpress.com/cursors/
ETA: Ok. Ignore what I wrote. Listen to someone else. Apparently it's wrong, as I got down voted.
What tpdi said is correct. You have to do something with the cursor after you declare it.
Here's an example using two cursors in nested loops
PROCEDURE update_insert_tree (exid_in IN NUMBER, outvar_out OUT VARCHAR2)
IS
nxtid NUMBER;
phaseid NUMBER;
rowcounter1 NUMBER;
BEGIN
rowcounter1 := 0;
outvar_out := 0;
FOR acur IN (SELECT dept_exercise_id, phase
FROM ep_dept_exercise
WHERE exercise_id = exid_in)
LOOP
<<dept_loop>>
FOR thecur IN (SELECT document_name, thelevel, sortnum, type_flag,
ex_save_id
FROM ep_exercise_save
WHERE exercise_id = exid_in)
LOOP
phaseid := acur.phase;
IF phaseid = 0
THEN
phaseid := 10;
UPDATE ep_dept_exercise
SET phase = 10
WHERE dept_exercise_id = acur.dept_exercise_id;
END IF;
<<doc_loop>>