How To Return an Oracle Ref Cursor to a .NET DataReader Object by Using the .NET Managed Provider for Oracle (322160)

SUMMARY

This step-by-step article describes how to use the .NET Managed Provider for Oracle to pass an input parameter to retrieve a Ref Cursor from an Oracle stored procedure by using the OracleDataReader object.

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Requirements

The following list outlines the recommended hardware, software, network infrastructure, and service packs that are required:

• Microsoft Windows 2000 Professional, Windows 2000 Server, Windows 2000 Advanced Server, or Windows XP Professional
• Microsoft Visual Studio .NET
• Oracle Client 8.1.7 or later
• Microsoft .NET Managed Provider for Oracle

NOTE: To download the .NET Managed Provider for Oracle, visit the following Microsoft Web site: This article assumes that you are familiar with the following topics:

• Visual Basic .NET
• ADO.NET fundamentals and syntax

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Create the Oracle Tables

This example uses tables that are defined in the Oracle Scott/Tiger schema. By default, the Oracle Scott/Tiger schema is included with a standard Oracle installation.

If this schema does not exist, you must run the following table and insert scripts for the tables:

   CREATE TABLE DEPT
   (DEPTNO NUMBER(2,0) NOT NULL, 
   DNAME VARCHAR2(14) NULL, 
   LOC VARCHAR2(13) NULL,
   PRIMARY KEY (DEPTNO)
   );

   INSERT INTO Dept VALUES(11,'Sales','Texas');
   INSERT INTO Dept VALUES(22,'Accounting','Washington');
   INSERT INTO Dept VALUES(33,'Finance','Maine');

   CREATE TABLE EMP
   (EMPNO NUMBER(4,0) NOT NULL, 
   ENAME VARCHAR2(10) NULL, 
   JOB VARCHAR2(9) NULL, 
   MGR NUMBER(4,0) NULL, 
   SAL NUMBER(7,2) NULL, 
   COMM NUMBER(7,2) NULL, 
   DEPTNO NUMBER(2,0) NULL,
   FOREIGN KEY (DEPTNO) REFERENCES DEPT(DEPTNO),  
   PRIMARY KEY (EMPNO)
); 

   INSERT INTO Emp VALUES(123,'Bob','Sales',555,35000,12,11);
   INSERT INTO Emp VALUES(321,'Sue','Finance',555,42000,12,33);
   INSERT INTO Emp VALUES(234,'Mary','Account',555,33000,12,22);
				

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Create the Oracle Packages

Create the following Oracle package on the Oracle server:

CREATE OR REPLACE PACKAGE curspkg_join AS 
        TYPE t_cursor IS REF CURSOR ; 
        Procedure open_join_cursor1 (n_EMPNO IN NUMBER, io_cursor IN OUT t_cursor); 
   END curspkg_join;
   / 
				

Create the following Oracle package body on the Oracle server:

   CREATE OR REPLACE PACKAGE BODY curspkg_join AS
   Procedure open_join_cursor1 (n_EMPNO IN NUMBER, io_cursor IN OUT t_cursor) 
   IS 
        v_cursor t_cursor; 
   BEGIN 
        IF n_EMPNO <> 0 
THEN
             OPEN v_cursor FOR 
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME 
                  FROM EMP, DEPT 
                  WHERE EMP.DEPTNO = DEPT.DEPTNO 
                  AND EMP.EMPNO = n_EMPNO;

        ELSE 
             OPEN v_cursor FOR 
             SELECT EMP.EMPNO, EMP.ENAME, DEPT.DEPTNO, DEPT.DNAME 
                  FROM EMP, DEPT 
                  WHERE EMP.DEPTNO = DEPT.DEPTNO;

        END IF;
        io_cursor := v_cursor; 
   END open_join_cursor1; 
   END curspkg_join;
   / 
				

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Create the Visual Basic .NET Application

1. Follow these steps to create a Visual Basic Windows Application project:
   1. Start Microsoft Visual Studio .NET.
   2. On the File menu, point to New, and then click Project.
   3. Click Visual Basic Projects under Project Types, and then click Windows Application under Templates. By default, Form1 is added to the project.
2. On the Project menu, click Add Reference, and then set a reference to the System.Data.OracleClient namespace.
3. Drag a Button control from the toolbox to the form.
4. Add the following code at the top of the Code window:

   Imports System.Data.OracleClient
   					

5. Add the following code to the Button1_Click event of Form1:

           Dim Oraclecon As New OracleConnection("Password=pwd;" & _
                                                   "User ID=uid;Data Source=MyOracle;")
           Oraclecon.Open()
   
           Dim myCMD As New OracleCommand()
           myCMD.Connection = Oraclecon
           myCMD.CommandText = "curspkg_join.open_join_cursor1" 
           myCMD.CommandType = CommandType.StoredProcedure
           myCMD.Parameters.Add(New OracleParameter("io_cursor", OracleType.Cursor)).Direction = ParameterDirection.Output
           myCMD.Parameters.Add("n_Empno", OracleType.Number, 4).Value = 123
           Dim myReader As OracleDataReader
           Try
               myCMD.ExecuteNonQuery()
           Catch myex As Exception
               MsgBox(myex.Message)
           End Try
   
           myReader = myCMD.Parameters("io_cursor").Value
   
           Dim x, count As Integer
   
           count = 0
   
           Do While myReader.Read()
               For x = 0 To myReader.FieldCount - 1
                   Console.Write(myReader(x) & " ")
               Next
               Console.WriteLine()
               count += 1
           Loop
   
           MsgBox(count & " Rows Returned.")
   
           myReader.Close()
           Oraclecon.Close()
   
   					

6. Modify the OracleConnection string as appropriate for your environment.
7. Press F5 to compile and to run the program.

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Additional Information

When you use the OracleDataReader object, the Ref Cursor must be retrieved from the Parameters collection of the OracleCommand object.

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