Any SIMPLE way to fetch ALL results from a PL/SQL cursor? - sql

Question

The second part of the question: How to do the same (get ALL results, without any loops) with SQL*Plus.
I'm writing some PL/SQL scripts to test the data integrity using Jenkins.
I'm having a script like this:
declare
temp_data SOME_PACKAGE.someRefCurFunction; // type: CURSOR
DATA1 NUMBER;
DATA2 NUMBER;
DATA3 SOMETHING.SOMETHING_ELSE%TYPE;
begin
cursor := SOME_PACKAGE.someFunction('some',parameters,here);
LOOP
FETCH cursor INTO DATA1,DATA2,DATA3;
EXIT WHEN temp_data%NOTFOUND;
dbms_output.put_line(DATA1||','||DATA2||','||DATA3);
END LOOP;
end;
Relsults look like this:
Something1,,Something2
Something3,Something4,Something5
Something6,Something7,Something8
Sometimes the results are null, as in the 1st line. It doesnt matter, they should be.
The purpose of this script is simple - to fetch EVERYTHING from the cursor, comma separate the data, and print lines with results.
The example here is simple as hell, but It's just and example. The "Real life" Packages contain sometimes hundreds of variables, processing enormous database tables.
I need it to be as simple as possible.
Is there any method to fetch EVERYTHING from the cursor, comma separate single results if possible, and send it to output? The final output in the Jenkins test should be a text file, to be able to diff it with other results.
Thanks in advance :)

Answer 1

If you're truly open to a SQL*Plus script, rather than a PL/SQL block
SQL> set colsep ','
SQL> variable rc refcursor;
SQL> exec :rc := SOME_PACKAGE.someFunction('some',parameters,here);
SQL> print rc;
should execute the procedure and fetch all the data from your cursor. You could spool the resulting CSV output to a file using the spool command. Of course, you then may encounter issues where SQL*Plus isn't displaying the data in a clean format because of the linesize or other similar issues-- that may force you to add some additional SQL*Plus formatting commands (i.e. set linesize, column <<column name>> format <<format>>, etc.)
It's not obvious to me that a SQL*Plus script buys you much over writing some dynamic SQL that generates the PL/SQL script that you posted initially or (if you're on 12c) writing some code that uses dbms_sql to fetch data from the cursor that is returned.

Answer 2

The answer seems obvious. You currently have a function which returns a cursor itself returning a data set of hundreds (tho you show only three) fields. You want instead a single string with the comma-separated values. So change the function or write another one based on the same query.
package body SOME_PACKAGE
...
-- The current function
function someFunction ...
returns ref_cursor ...
-- create cursor based on:
select f1, f2, f3 --> Three (or n) fields
from ...
where ...;
return generated_cursor;
end function;
-- The new function
function someOtherFunction ...
returns ref_cursor ...
-- create cursor based on:
select f1 || ',' || f2 || ',' || f3 as StringField --> one string field
from ...
where ...;
return generated_cursor;
end function;
end package;
This isn't quite all that you asked for. It does save declaring variables (one instead of hundreds) to read the data in one row at a time, but you still read it in one row at a time instead of, as I read your question, reading in every row in one operation. But if such a super-fetch were possible, it would require massive amounts of memory. Sometimes we do things that just require massive amounts of memory and we just work with that the best we can. But your "requirement" seems to be only a matter of convenience for the developers. That, imnsho, lies way down in the list of priorities for consuming resources.
Developing a cursor that returns the data in the final form you want would seem to me to the best of all alternatives.