How To Retrieve Recordsets from Oracle Stored Procedures Using ADO

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: NOTE: The Recordsets created by the Microsoft ODBC Driver for Oracle , 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. You must have this driver to use the recordsets-from-stored-procedures functionality discussed in this Knowledge Base article: (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: NOTE: You must acquire and install the MDAC 2.1 or later stack for the sample in this article. The following Microsoft Knowledge Base article explains how to get the Oracle and MDAC components: MDAC 1.5 contains ADO 1.5 and the Microsoft ODBC Driver for Oracle version 2.0.

The MDAC 2.x stack, which includes the 2.573 driver, can be downloaded from the following Web address: 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

1. 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;
    / 
   					

2. 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;
   / 
   					

3. 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;
   / 
   					

4. Open a new project in Visual Basic 5.0 or 6.0 Enterprise edition. Form1 is created by default.
5. Place the following controls on the form:

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

6. 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.
7. 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

8. Go to the Project menu item and select References. Select the "Microsoft Active Data Objects 2.x Library."
9. 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: 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.