HOWTO: Retrieve Recordsets From Oracle Stored Procs Using ADO

ID: Q176086

The information in this article applies to:

Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
Microsoft ODBC for Oracle (2.73.7283.03), version 2.0
Microsoft ODBC for Oracle (2.573.2927), version 2.5

SUMMARY

This article shows how to create a Visual Basic 5.0 and ActiveX Data Objects (ADO) 1.5 project or a Visual Basic 6.0 and ADO 2.0 project that returns a typical Recordset from an Oracle stored procedure. This article builds on the concepts covered in the following Microsoft Knowledge Base article:

Q174679 HOWTO: Retrieve Typical Resultsets From Oracle Stored Procedures

It is almost identical to the following article in the Microsoft Knowledge Base article that covers the topic using Remote Data Objects (RDO):

Q174981 HOWTO: Retrieve Typical Resultsets From Oracle Stored Procedures

MORE INFORMATION

The following Knowledge Base article gives an in-depth example, using RDO, of all the possible ways to return a Recordset back from a stored procedure. The example in this article is a simplified version:

Q174679 HOWTO: Retrieve Resultsets from Oracle Stored Procedures

NOTE: The Recordsets created by the Microsoft ODBC Driver for Oracle versions 2.0 and 2.5, using Oracle stored procedures, are Read Only and Static. Retrieving a Recordset requires you to create an Oracle Package.

You can create the sample project in this article in Visual Basic 5.0 or 6.0 and use ADO to access and manipulate the Recordsets created by the Microsoft ODBC Driver for Oracle version 2.0 or 2.5. You must have this driver to use the recordsets-from-stored-procedures functionality discussed in this Knowledge Base article:

Q174679 HOWTO: Retrieve Resultsets from Oracle Stored Procedures

(Currently, it is the only driver on the market that can return a Recordset from a stored procedure.) If you want additional information about using Visual Basic with Oracle, please see the following Knowledge Base article, which uses RDO 2.0 in its examples:

Q167225 HOWTO: Access an Oracle Database Using RDO

NOTE: You will need to acquire and install the MDAC 1.5 or 2.0 stack for the sample in this article. The following Microsoft Knowledge Base article explains how to get the Oracle and MDAC components:

Q175018 HOWTO: Acquire and Install the Microsoft Oracle ODBC Driver

MDAC 1.5 contains ADO 1.5 and the Microsoft ODBC Driver for Oracle version 2.0.

The MDAC 2.0 stack, which includes the 2.5 driver, can be downloaded from the following Web address:

http://www.microsoft.com/data/

This article is broken up into two parts. The first part is a step-by-step procedure for creating the project. The second part is a detailed discussion about the interesting parts of the project.

Step-by-Step Example

Run the following DDL script on your Oracle server:


DROP TABLE person;

CREATE TABLE person
 (ssn     NUMBER(9) PRIMARY KEY,
  fname   VARCHAR2(15),
  lname   VARCHAR2(20));

INSERT INTO person VALUES(555662222,'Sam','Goodwin');

INSERT INTO person VALUES(555882222,'Kent','Clark');

INSERT INTO person VALUES(666223333,'Jane','Doe');

COMMIT;
 /

Create the following package on your Oracle server:


CREATE OR REPLACE PACKAGE packperson
  AS
    TYPE tssn is TABLE of  NUMBER(10)
    INDEX BY BINARY_INTEGER;
    TYPE tfname is TABLE of VARCHAR2(15)
    INDEX BY BINARY_INTEGER;
    TYPE tlname is TABLE of VARCHAR2(20)
    INDEX BY BINARY_INTEGER;

    PROCEDURE allperson
            (ssn    OUT     tssn,
             fname  OUT     tfname,
             lname  OUT     tlname);
    PROCEDURE oneperson
        (onessn IN      NUMBER,
         ssn    OUT     tssn,
             fname  OUT     tfname,
             lname  OUT     tlname);
END packperson;
/

Create the following package body on your Oracle server:


CREATE OR REPLACE PACKAGE BODY packperson
AS

PROCEDURE allperson
            (ssn    OUT     tssn,
             fname  OUT     tfname,
             lname  OUT     tlname)
IS
    CURSOR person_cur IS
            SELECT ssn, fname, lname
            FROM person;

    percount NUMBER DEFAULT 1;

BEGIN
    FOR singleperson IN person_cur
    LOOP
            ssn(percount) := singleperson.ssn;
            fname(percount) := singleperson.fname;
            lname(percount) := singleperson.lname;
            percount := percount + 1;
    END LOOP;
END;

PROCEDURE oneperson
      (onessn  IN    NUMBER,
             ssn     OUT   tssn,
             fname   OUT   tfname,
             lname   OUT   tlname)
IS
 CURSOR person_cur IS
           SELECT ssn, fname, lname
           FROM person
           WHERE ssn = onessn;

    percount NUMBER DEFAULT 1;

BEGIN
    FOR singleperson IN person_cur
    LOOP
            ssn(percount) := singleperson.ssn;
            fname(percount) := singleperson.fname;
            lname(percount) := singleperson.lname;
            percount := percount + 1;
    END LOOP;
END;
END;
/

Open a new project in Visual Basic 5.0 or 6.0 Enterprise edition. Form1 is created by default.

Place the following controls on the form:


Control     Name             Text/Caption
-----------------------------------------
Button      cmdGetEveryone   Get Everyone
Button      cmdGetOne        Get One

From the Tools menu, select the Options item. Click the "Default Full Module View" option and then click OK. This will allow you to view all of the code for this project.

Paste the following code into your code window:


Option Explicit
Dim Cn As ADODB.Connection
Dim CPw1 As ADODB.Command
Dim CPw2 As ADODB.Command
Dim Rs As ADODB.Recordset
Dim Conn As String
Dim QSQL As String
Dim inputssn As Long

Private Sub cmdGetEveryone_Click()

  Set Rs.Source = CPw1

  Rs.Open

  While Not Rs.EOF
      MsgBox "Person data: " & Rs(0) & ", " & Rs(1) & ", " & Rs(2)
      Rs.MoveNext
  Wend

  Rs.Close

End Sub

Private Sub cmdGetOne_Click()

  Set Rs.Source = CPw2

  inputssn = InputBox("Enter the SSN you wish to retrieve:")

  CPw2(0) = inputssn

  Rs.Open

  MsgBox "Person data: " & Rs(0) & ", " & Rs(1) & ", " & Rs(2)

  Rs.Close

End Sub

Private Sub Form_Load()

  'Replace <User ID>, <Password>, and <Server> with the
  'appropriate parameters.
  Conn = "UID=*****;PWD=*****;driver=" _
         & "{Microsoft ODBC for Oracle};SERVER=dseOracle;"

  Set Cn = New ADODB.Connection
  With Cn
      .ConnectionString = Conn
      .CursorLocation = adUseClient
      .Open
  End With

  QSQL = "{call packperson.allperson({resultset 9, ssn, fname, " _
         & "lname})}"

  Set CPw1 = New ADODB.Command
  With CPw1
      Set .ActiveConnection = Cn
      .CommandText = QSQL
      .CommandType = adCmdText
  End With

  QSQL = "{call packperson.oneperson(?,{resultset 2, ssn, fname, " _
         & "lname})}"

  Set CPw2 = New ADODB.Command
  With CPw2
      Set .ActiveConnection = Cn
      .CommandText = QSQL
      .CommandType = adCmdText
      .Parameters.Append .CreateParameter(, adInteger, adParamInput)
  End With

  Set Rs = New ADODB.Recordset
  With Rs
      .CursorType = adOpenStatic
      .LockType = adLockReadOnly
  End With

End Sub

Private Sub Form_Unload(Cancel As Integer)

  Cn.Close
  Set Cn = Nothing
  Set CPw1 = Nothing
  Set CPw2 = Nothing
  Set Rs = Nothing

End Sub

Go to the Project menu item and select References. Select the "Microsoft Active Data Objects 1.5 Library."

Run the project. When you click on the "Get Everyone" button, it executes this query:


QSQL = "{call packperson.allperson({resultset 9, ssn, fname, "_
               & "lname})}"

This query is executing the stored procedure "allperson," which is in the package "packperson" (referenced as "packperson.allperson"). There are no input parameters and the procedure is returning three arrays (ssn, fname, and lname) each with nine or fewer records. As stated in the following Knowledge Base article:

Q174679 HOWTO: Retrieve Resultsets from Oracle Stored Procedures

you must specify the maximum number of rows you will be returning. Please refer to the Microsoft ODBC Driver for Oracle Help File and Knowledge Base article Q174679 for more information on this issue.

When you click on the "Get One," button it brings up an input box that prompts you for an SSN. Once you input a valid SSN and click OK, this query is executed:


QSQL = "{call packperson.oneperson(?,{resultset 2, ssn, fname, "_
           & "lname})}"

The stored procedure, packperson.oneperson, uses a single input parameter as the selection criteria for the Recordset it creates. Just like packperson.allperson, the Recordset is constructed using the table types defined in packperson. (See Knowledge Base article Q174679 for more information.)

NOTE: You can only define input parameters for Oracle stored procedures that return a Recordset. You cannot define output parameters for these stored procedures.

These two stored procedures cover the basic uses of stored procedures that return Recordsets. The first one will give you a predefined set of records (i.e. everyone) and the second one will give you a set of records (or just one record) based on one or more input parameters. Once you have these recordsets, you can do inserts, updates, and deletes either through stored procedures or SQL that you create on the client.

REFERENCES

Microsoft ODBC Driver for Oracle Help File

"Oracle PL/SQL Programming" by Steven Feuerstein

"Hitchhiker's Guide to Visual Basic & SQL Server" by William Vaughn

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:

Q174679 HOWTO: Retrieve Resultsets from Oracle Stored Procedures

Q175018 HOWTO: Acquire and Install the Microsoft Oracle ODBC Driver

Q174981 HOWTO: Retrieve Typical Resultsets from Oracle Stored Procedures

Q167225 HOWTO: Access an Oracle Database Using ROD

Additional query words: oracle stored procedures ado msorcl32.dll kbVB500 kbVB600 kbADO150 kbADO200 kbOracle kb Driver kbODBC kbDatabase package

Keywords : kbDatabase kbGrpVB kbGrpVBDB kbGrpMDAC kbDSupport kbADO210sp2 kbMDAC210SP2
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbhowto