Can we return a Array of varchar2 from a function ?

Question

Hello,
i have a sql query that returns some rows. I want to define that query inside a function and want to retrieve the results in an array .Finally i want to retrieve those values in array in my .NET runtime . How can i achieve this ?

Answer 1

bootstrap wrote:
CREATE OR REPLACE function f_func(dept varchar2) return (what will be return type here ?)As Tubs said - ref cursor.
Any other choice is likely very wrong.
select statement...returning a resultset containing more than one rows..Cursors are not result sets. Cursors are not result sets. Repeat this over and over again.
A cursor is a program. The results from it is the output of the program. There is no so-called result set created in memory containing the output of that cursor.
The flaw in your approach is to fetch the output of this program, and storing it in very expensive server memory (called the PGA in Oracle) - for returning data as a primitive non-scalar data structure to the client.
Returning a ref cursor (aka a pointer to a cursor) means that you give the client direct access to the interface of that cursor program. Allowing the client to directly fetch and consume the output of that program. Enabling the client to deal with the standard SQL (cursor) interface.
A significantly more performant and scalable method than to create a primitive result set cache in server memory for the output and then shipping that (as a non-standard data structure) to a client.
A ref cursor interface can returns millions of rows and GBs of data. How many rows do you think this approach of yours will take? How many clients can call that same PL/SQL interface of yours at the same time, before the memory footprint of caching SQL data in the PGA for external clients exceeds free server memory?
Do you realise what happens next? Swap daemons trashing badly consuming most of the CPU (even starving the kernel itself). If you're lucky, the server will crash quickly. If not, even console access to the server in attempt to fix mess will be something like typing one character every 60 seconds at the console.