Result Sets from Stored Procedures In Oracle

A frequently asked question is:

I'd like to know whether ORACLE supports procedures (functions) which

returns result sets.

The answer is most definitely yes.  In short, it'll look like this for a function:

create or replace function sp_ListEmp return types.cursortype

as

    l_cursor    types.cursorType;

begin

    open l_cursor for select ename, empno from emp order by ename;

    return l_cursor;

end;

/

Or like this for a procedure:

create or replace procedure getemps( p_cursor in out types.cursorType )

as

begin

open p_cursor for select ename, empno from emp order by ename;

end;

With 7.2 on up of the database you have cursor variables.  Cursor variables are cursors opened by a pl/sql routine and fetched from by another application or pl/sql routine (in 7.3 pl/sql routines can fetch from cursor variables as well as open them). The cursor variables are opened with the privelegs of the owner of the procedure and behave just like they were completely contained within the pl/sql routine. It uses the inputs to decide what database it will run a query on.

Here is an example:

create or replace package types

as

    type cursorType is ref cursor;

end;

/

create or replace function sp_ListEmp return types.cursortype

as

    l_cursor    types.cursorType;

begin

    open l_cursor for select ename, empno from emp order by ename;

    return l_cursor;

end;

/

create or replace procedure getemps( p_cursor in out types.cursorType )

as

begin

open p_cursor for select ename, empno from emp order by ename;

end;

/

examples for SQLPlus, Pro*C, Java/JDBC, ODBC, ADO/ASP, DBI Perl and OCI follow:

REM SQL*Plus commands to use a cursor variable

variable c refcursor

exec :c := sp_ListEmp

print c

exec getEmps( :c )

print c

and the Pro*C to use this would look like:

static void process()

{

EXEC SQL BEGIN DECLARE SECTION;

    SQL_CURSOR  my_cursor;

    VARCHAR     ename[40];

    int         empno;

EXEC SQL END DECLARE SECTION;

    EXEC SQL WHENEVER SQLERROR DO sqlerror_hard();

    EXEC SQL ALLOCATE :my_cursor;

    EXEC SQL EXECUTE BEGIN

        :my_cursor := sp_listEmp;

    END; END-EXEC;

    for( ;; )

    {

        EXEC SQL WHENEVER NOTFOUND DO break;

        EXEC SQL FETCH :my_cursor INTO :ename, empno;

        printf( "'%.*s', %d

", ename.len, ename.arr, empno );

    }

    EXEC SQL CLOSE :my_cursor;

}

And the java to use this could be:

import java.sql.*;

import java.io.*;

import oracle.jdbc.driver.*;

class curvar

{

  public static void main (String args [])

                     throws SQLException, ClassNotFoundException

  {

      String driver_class = "oracle.jdbc.driver.OracleDriver";

      String connect_string = "jdbc:oracle:thin:@slackdog:1521:oracle8";

      String query = "begin :1 := sp_listEmp; end;";

      Connection conn;

      Class.forName(driver_class);

      conn = DriverManager.getConnection(connect_string, "scott", "tiger");

      CallableStatement cstmt = conn.prepareCall(query);

      cstmt.registerOutParameter(1,OracleTypes.CURSOR);

      cstmt.execute();

      ResultSet rset = (ResultSet)cstmt.getObject(1);

      while (rset.next ())

        System.out.println( rset.getString (1) );

      cstmt.close();

  }

}

The following is thanks to [email protected] (mark tomlinson)..

If you use ODBC here is a working example, but it requires the use of the

8.0.5.2.0 or later Oracle ODBC driver, and an 8.0.5 server.

'

' 1) Create a form with 1 Text control (Text1) and 1 List Control (List1) and

'    1 Button (btnExecute).

' 2) The only code that you need is a Click method on your button. Here is the Code.

'

'

Private Sub btnExecute_Click()

'PL/SQL Code

'===========

'

'CREATE OR REPLACE package reftest as

' cursor c1 is select ename from emp;

' type empCur is ref cursor return c1%ROWTYPE;

' Procedure GetEmpData(en in varchar2,EmpCursor in out empCur);

'END;

'

'

'CREATE OR REPLACE package body reftest as

'   Procedure GetEmpData

'(en in varchar2,EmpCursor in out empCur) is

'begin

' open EmpCursor for select ename from emp where ename LIKE en;

'end;

'end;

'

     Dim cn As New rdoConnection

     Dim qd As rdoQuery

     Dim rs As rdoResultset

     Dim cl As rdoColumn

     Static Number As Integer

     List1.Clear

     Number = 0

     cn.Connect = "uid=scott; pwd=tiger; DSN=MSLANGORL;"

     'enable the MS Cursor library

     cn.CursorDriver = rdUseOdbc

     'Make the connection

     cn.EstablishConnection rdNoDriverPrompt

     sSQL = "{call RefTest.GetEmpData(?,?)}"

     Set qd = cn.CreateQuery("", sSQL)

     qd.rdoParameters(0).Type = rdTypeVARCHAR

     qd(0).Direction = rdParamInputOutput

     qd(0).Value = Text1.Text

     qd.rdoParameters(1).Type = rdTypeVARCHAR

     'Dynamic or Keyset is meaningless here

     Set rs = qd.OpenResultset(rdOpenStatic)

     Do

        Debug.Print

        Debug.Print

        Do Until rs.EOF

            For Each cl In rs.rdoColumns

                 If IsNull(cl.Value) Then

                    List1.AddItem "(null)"

                    ' Debug.Print " "; cl.Name; "NULL"; Error trap for

null fields

                Else

                    List1.AddItem cl.Value

                    ' Debug.Print " "; cl.Name; " "; cl.Value;

                End If

            Next

            Debug.Print

            rs.MoveNext

        Loop

     Loop While rs.MoreResults

     cn.Close

End Sub