DOCUMENT:Q174679 11-SEP-2001 [vbwin]
TITLE :HOWTO: Retrieve Resultsets from Oracle Stored Procedures
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER::5.0,6.0,Build 2.573.2927,Build 2.73.7283.03
OPER/SYS:
KEYWORDS:kbDatabase kbDriver kbODBC kbOracle kbRDO kbVBp kbVBp500 kbVBp600 kbDSupport
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The information in this article applies to:
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
- Microsoft ODBC for Oracle version 2.0 Build 2.73.7283.03
- Microsoft ODBC for Oracle version 2.5 Build 2.573.2927
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SUMMARY
=======
This article demonstrates how to use Visual Basic Enterprise Edition, Remote
Data Object (RDO), the Microsoft ODBC Driver for Oracle version 2.0 and higher,
and an Oracle PL/SQL package to retrieve resultsets from an Oracle stored
procedure.
MORE INFORMATION
================
With the release of the Microsoft ODBC Driver for Oracle version 2.0 and higher,
you can now retrieve resultsets from Oracle stored procedures. By creating
Oracle stored procedures that return parameters of type TABLE, you can return
row and column data that can then be manipulated and displayed as a resultset.
This article uses the example in the Help file for the Microsoft ODBC Driver for
Oracle v2.0 and shows how to use that example in Visual Basic.
NOTE: The resultsets created by the Microsoft ODBC Driver for Oracle version 2.0
and 2.5 using Oracle stored procedures are READ ONLY and STATIC. To retrieve a
resultset requires that an Oracle Package be created.
Before you can start working with the Visual Basic application, you must create
an Oracle package called SimplePackage. SimplePackage is taken from the Help
File for Microsoft ODBC Driver for Oracle: Advanced Topics: "Returning Array
Parameters from Stored Procedures."
The following package definition and package body for SimplePackage need to be
added to your Oracle server either through SQL*Plus or through the Data Tools in
Visual Basic 5.0 Enterprise edition:
Step 1
------
CREATE OR REPLACE PACKAGE SimplePackage AS
TYPE t_id is TABLE of NUMBER(5)
INDEX BY BINARY_INTEGER;
TYPE t_Course is TABLE of VARCHAR2(10)
INDEX BY BINARY_INTEGER;
TYPE t_Dept is TABLE of VARCHAR2(5)
INDEX BY BINARY_INTEGER;
TYPE t_pk1Type1 IS TABLE OF VARCHAR2(100)
INDEX BY BINARY_INTEGER;
TYPE t_pk1Type2 IS TABLE OF NUMBER(5)
INDEX BY BINARY_INTEGER;
PROCEDURE proc1
( o_id OUT t_id,
ao_course OUT t_Course,
ao_dept OUT t_Dept
);
PROCEDURE proc2
(
i_Arg1 IN NUMBER,
ao_Arg2 OUT t_pk1Type1,
ao_Arg3 OUT t_pk1Type2
);
END SimplePackage;
Step 2
------
CREATE OR REPLACE PACKAGE BODY SimplePackage AS
PROCEDURE proc1
(
o_id OUT t_id,
ao_course OUT t_Course,
ao_dept OUT t_Dept
)
AS
BEGIN
o_id(1):= 200;
ao_course(1) := 'M101';
ao_dept(1) := 'EEE' ;
o_id(2) := 201;
ao_course(2) := 'PHY320';
ao_dept(2) := 'ECE' ;
END proc1;
PROCEDURE proc2
(
i_Arg1 IN NUMBER,
ao_Arg2 OUT t_pk1Type1,
ao_Arg3 OUT t_pk1Type2
)
AS
i NUMBER;
BEGIN
FOR i IN 1 .. i_Arg1 LOOP
ao_Arg2(i) := 'Row Number ' || to_char(i);
END LOOP;
FOR i IN 1 .. i_Arg1 LOOP
ao_Arg3(i) := i;
END LOOP;
END proc2;
END SimplePackage;
Once SimplePackage is loaded and compiled on the Oracle server, you can start
working on the Visual Basic application.
Step-by-Step Example
--------------------
This example project uses a simple form to call the two procedures in the
SimplePackage package. Both procedures (Proc1 and Proc2) return arrays (Oracle
TABLE data type) that are converted to resultsets by the Microsoft ODBC Driver
for Oracle version 2.0 or 2.5. These resultsets are manipulated and displayed in
the project using the Remote Data Object. Here are the steps to create the
project:
1. Open a new project in Visual Basic 5.0 Enterprise edition. Form1 is created
by default.
2. Place the following controls on the form:
Control Name Text/Caption
----------------------------------
Button cmdProc1A Proc1A
Button cmdProc1B Proc1B
Button cmdProc2A Proc2A
Button cmdProc2B Proc2B
Text Box txtZero1
Text Box txtZero2
Text Box txtOne1
Text Box txtOne2
NOTE: The text boxes should be laid out in the following grid format:
txtZero1 txtOne1
txtZero2 txtOne2
1. From the Tools menu, select the Options item. Click the Default Full Module
View option and then click OK. This allows you to view all of the code for
this project.
2. Paste the following code into the General Declarations section of the new
form:
Option Explicit
Dim Cn As rdoConnection
Dim En As rdoEnvironment
Dim CPw1 As rdoQuery
Dim CPw2 As rdoQuery
Dim CPw3 As rdoQuery
Dim CPw4 As rdoQuery
Dim Rs As rdoResultset
Dim Conn As String
Dim QSQL As String
Private Sub cmdProc1A_Click()
Set Rs = CPw1.OpenResultset(rdOpenStatic, rdConcurReadOnly)
txtZero1 = Rs(0)
txtOne1 = Rs(1) & " " & Rs(2)
Rs.MoveNext
txtZero2 = Rs(0)
txtOne2 = Rs(1) & " " & Rs(2)
Rs.Close
MsgBox "Done"
End Sub
Private Sub cmdProc1B_Click()
Dim tempOne1 As String
Dim tempOne2 As String
Set Rs = CPw2.OpenResultset(rdOpenForwardOnly, rdConcurReadOnly)
txtZero1 = Rs(0)
Rs.MoveNext
txtZero2 = Rs(0)
Rs.MoreResults
tempOne1 = Rs(0)
Rs.MoveNext
tempOne2 = Rs(0)
Rs.MoreResults
txtOne1 = tempOne1 & " " & Rs(0)
Rs.MoveNext
txtOne2 = tempOne2 & " " & Rs(0)
Rs.Close
MsgBox "Done"
End Sub
Private Sub cmdProc2A_Click()
CPw3(0) = 2
Set Rs = CPw3.OpenResultset(rdOpenForwardOnly, rdConcurReadOnly)
txtZero1 = Rs(0)
txtOne1 = Rs(1)
Rs.MoveNext
txtZero2 = Rs(0)
txtOne2 = Rs(1)
Rs.Close
MsgBox "Done"
End Sub
Private Sub cmdProc2B_Click()
CPw4(0) = 2
Set Rs = CPw4.OpenResultset(rdOpenForwardOnly, rdConcurReadOnly)
txtZero1 = Rs(0)
Rs.MoveNext
txtZero2 = Rs(0)
Rs.MoreResults
txtOne1 = Rs(0)
Rs.MoveNext
txtOne2 = Rs(0)
Rs.Close
MsgBox "Done"
End Sub
Private Sub Form_Load()
Conn = "UID=<user ID>;PWD=<password>;"_
& "driver={Microsoft ODBC for Oracle};SERVER=RonOracle;"
Set En = rdoEnvironments(0)
En.CursorDriver = rdUseOdbc
Set Cn = En.OpenConnection("", rdDriverNoPrompt, False, Conn)
QSQL = "{call SimplePackage.Proc1({resultset 3, o_id , " _
& "ao_course, ao_dept})}"
Set CPw1 = Cn.CreateQuery("", QSQL)
QSQL = "{call SimplePackage.Proc1({resultset 3, o_id}, " _
& "{resultset 3, ao_course}, {resultset 3, ao_dept})}"
Set CPw2 = Cn.CreateQuery("", QSQL)
QSQL = "{call SimplePackage.Proc2(?,{resultset 3, ao_Arg2," _
& " ao_Arg3})}"
Set CPw3 = Cn.CreateQuery("", QSQL)
QSQL = "{call SimplePackage.Proc2(?,{resultset 3, ao_Arg2}, " _
& "{resultset 3, ao_Arg3})}"
Set CPw4 = Cn.CreateQuery("", QSQL)
End Sub
Private Sub Form_Unload(Cancel As Integer)
En.Close
End Sub
3. Run the project.
Note that the array returned by the stored procedure is being turned into an RDO
resultset. The code in this example is fairly standard except for the creation
and execution of the Oracle stored procedures.
The query objects created in the code each do something a little different. The
first one is the simplest and probably the most common way to call this type of
stored procedure:
QSQL = "{call SimplePackage.Proc1({resultset 3, o_id , " _
& "ao_course, ao_dept})}"
Within the call statement, you must supply the keyword RESULTSET followed by the
maximum number of rows you will be returning.
NOTE: If you return more than the maximum specified, you get an error. If you
return less, everything works fine.
After the resultset keyword and maximum number of rows, this form of the call
statement supplies the stored procedure parameter list. Each parameter is
actually an array (or Oracle TABLE variable) containing all of the elements for
a given column of a resultset. In this example (Proc1), there are three columns
in the returning resultset represented by the three arrays o_id, ao_course, and
ao_dept.
NOTE: This parameter list needs to appear exactly as it does in the stored
procedure.
The next query object does something different:
QSQL = "{call SimplePackage.Proc1({resultset 3, o_id}, " _
& "{resultset 3, ao_course}, {resultset 3, ao_dept})}"
This form of the call statement is actually creating three resultsets; one for
each column in the original (or returning) resultset. Note that you must use the
keyword RESULTSET and the maximum number of rows for each resultset. This form
of the call statement is actually giving the resultset for each array declared
in the parameter list.
The next query object is taking in an input parameter and then returning
resultset as before:
QSQL = "{call SimplePackage.Proc2(?,{resultset 3, ao_Arg2,"
& " ao_Arg3})}"
Note that not much has changed. An input placeholder (?) has been added to the
beginning of the parameter list, where it must be if it is to be used.
The last form of the call statement is the multiple result example from above
with an input placeholder added to the parameter list:
QSQL = "{call SimplePackage.Proc2(?,{resultset 3, ao_Arg2}, " _
& "{resultset 3, ao_Arg3})}"
Once the query object is defined, everything else in the project is standard RDO;
setting input and output parameters, moving within the RDO resultsets, and
moving between resultsets.
REFERENCES
==========
Help file for Microsoft ODBC Driver for Oracle: Advanced Topics: "Returning
Array Parameters from Stored Procedures"
Visual Basic 5.0 Enterprise Documentation: The Guide to Building Client/Server
Applications with Visual Basic: Data Access Options: "Remote Data Objects (RDO)
- Chapter 11"
For more information on working with RDO 2.0 and Oracle, please click on the
article number below to see the article in the Microsoft Knowledge Base:
Q167225 HOWTO: Access an Oracle Database Using RDO
(c) Microsoft Corporation 1999, All Rights Reserved.
Contributions by Sam Carpenter, Microsoft Corporation
Additional query words:
======================================================================
Keywords : kbDatabase kbDriver kbODBC kbOracle kbRDO kbVBp kbVBp500 kbVBp600 kbDSupport
Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbODBCSearch kbVB500 kbVB600 kbODBCOracle273728303 kbODBCOracle25732927 kbODBCOracle200Search kbODBCOracle250Search
Version : :5.0,6.0,Build 2.573.2927,Build 2.73.7283.03
Issue type : kbhowto
=============================================================================
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