2 Using Oracle Objects for OLE with Automation Clients

Using Automation Clients Overview

Oracle Objects for OLE (OO4O) is designed to provide quick and efficient access to the data in an Oracle database using various programming or scripting languages.

OO4O can be easily used with Visual Basic, Excel, Active Server Pages, Internet Information Server (IIS), and other development tools.

Oracle Data Control with Visual Basic allows another method of accessing Oracle data.

Examples are provided for specific methods and properties in this developer's guide. Additionally, example programs are installed with Oracle Objects for OLE and are located in the ORACLE_BASE\\ORACLE_HOME\oo4o\ directory under VB, EXCEL, IIS, CPP, and so on.

A Quick Tour of OO4O with Visual Basic is also provided.

Demonstration Schema and Code Examples

The code examples included in this developer's guide and the example applications shipped with Oracle Objects for OLE are designed to work with a demonstration schema (database tables and other objects) and a demonstration user and password, scott/tiger. Code examples are located in the ORACLE_BASE\\ORACLE_HOME\oo4o directory.

Using Oracle Objects for OLE Automation with Visual Basic

This example contains code fragments that demonstrate how to create all objects required by a dynaset and then create the dynaset itself.

1. Start Visual Basic and create a new project. From the Project menu, select References and check InProcServer 5.0 Type Library.

   
   Description of the illustration o4o00003.gif
   
   

2. Start Visual Basic and create a new project. Then, add the following code to the Declarations section of a form:

   ... 
   ' Declare variables 
   Dim OraSession As OraSession 
   Dim OraDatabase As OraDatabase 
   Dim OraDynaset As OraDynaset 
   Dim OraFields As OraFields
   

3. Add the following code to the load procedure associated with the form to display the Oracle data:

   ' Create the OraSession Object. The argument to CreateObject is the 
   ' name by which the OraSession object is known to the OLE system. 
   Set OraSession = CreateObject("OracleInProcServer.XOraSession") 
    
   ' Create the OraDatabase Object by opening a connection to Oracle.
   Set OraDatabase = OraSession.OpenDatabase("ExampleDb", "scott/tiger", 0&) 
    
   ' Create the OraDynaset Object. 
   Set OraDynaset = OraDatabase.CreateDynaset("select * from emp", 0&) 
    
   ' You can now display or manipulate the data in the dynaset. For example: 
   Set OraFields = OraDynaset.fields 
   OraDynaset.movefirst 
   Do While Not OraDynaset.EOF 
   MsgBox OraFields("ename").Value 
   OraDynaset.movenext 
   Loop 
   End Sub 
   

4. Run the form to view the results.

Using OO4O Automation with Active Server Pages (ASP)

This example uses Active Server Pages (ASP) in a Microsoft Internet Information Server (IIS) to demonstrate the connection pooling feature of Oracle Objects for OLE. The sample code executes a SQL SELECT query and returns the result as an HTML table. The database connection used in this script is obtained from a pool that is created when the global.asa file is executed.

To use Oracle Objects for OLE with OLE Automation and IIS, you need to install IIS 3.0 or later, including all ASP extensions. On the computer where IIS is running, an Oracle database must also be accessible.

1. Start SQL*Plus and log in to the Oracle database as scott/tiger.

   Create the following PL/SQL procedures:

   -- creates PL/SQL package to be used in ASP demos
   create or replace package ASP_demo as 
       --cursor c1 is select * from emp; 
       type empCur is ref cursor; 
   PROCEDURE GetCursor(p_cursor1 in out empCur, indeptno IN NUMBER, 
                     p_errorcode OUT NUMBER); 
   END ASP_demo;
   /
   

   Create or replace the ASP_demo package body as follows:

   PROCEDURE GetCursor(p_cursor1 in out empCur, indeptno IN NUMBER, 
                    p_errorcode OUT NUMBER) is 
   BEGIN 
       p_errorcode:= 0; 
       open p_cursor1 for select * from emp where deptno = indeptno; 
   EXCEPTION 
       When others then 
       p_errorcode:= SQLCODE; 
   END GetCursor; 
   ...
   

   END ASP_demo; 
   /
    
   

2. Create the Active Server Pages (ASP) sample code. The OO4O related code is in bold.

   'GLOBAL.ASA 
   
   <OBJECT RUNAT=Server SCOPE=Application ID=OraSession 
                 PROGID="OracleInProcServer.XOraSession"></OBJECT> 
   <SCRIPT LANGUAGE=VBScript RUNAT=Server> 
   Sub Application_OnStart 
    
   'Get an instance of the Connection Pooling object and 
   'create a pool of OraDatabase 
   OraSession.CreateDatabasePool 1,40,200,"exampledb", "scott/tiger",  0 
   End Sub 
    
   'OO4ODEMO.ASP 
   
   <html> 
   <head> 
   <title>Oracle Objects For OLE (OO4O) </title> 
   </head> 
   <body BGCOLOR="#FFFFFF"> 
   <font FACE="ARIAL,HELVETICA"> 
   <h2 align="center">Oracle Objects For OLE (OO4O) </h2> 
   <form ACTION="OO4ODEMO.asp" METHOD="POST"> 
   <% 
   SqlQuery = Request.Form("sqlquery") 
   %> 
   <p>This sample executes a SQL SELECT query and returns the result as an HTML table. The database connection used in this script is obtained from a pool that is created when the <strong>global.asa</strong> is executed. </p> 
   <p>SQL Select Query: <input SIZE="48" NAME="sqlquery"> </p> 
   <p><input TYPE="SUBMIT"> <input TYPE="RESET"> <input LANGUAGE="VBScript" TYPE="button" VALUE="Show ASP Source" ONCLICK="Window.location.href = &quot;oo4oasp.htm&quot;" 
    
   NAME="ShowSrc"></p> 
   </form> 
   <% 
   If SqlQuery = "" Then 
   %> 
   <% Else %> 
   <table BORDER="1"> 
   <% 
   Set OraDatabase = OraSession.GetDatabaseFromPool(10) 
   Set OraDynaset = OraDatabase.CreateDynaset(SqlQuery,0) 
   Set Columns = OraDynaset.Fields 
   %> 
   <tr> 
   <td><table BORDER="1"> 
   <tr> 
   <% For i = 0 to Columns.Count - 1 %> 
   <td><b><% = Columns(i).Name %></b></td> 
   <% Next %> 
   </tr> 
   <% while NOT OraDynaset.EOF %> 
   <tr> 
   <% For col = 0 to Columns.Count - 1 %> 
   <td><% = Columns(col) %> 
   </td> 
   <% Next %> 
   </tr> 
   <% OraDynaset.MoveNext %> 
   <% WEnd %> 
   </table> 
    
   <p></font><%End If%> </p> 
   <hr> 
   </td> 
   </tr> 
   </table> 
   </body> 
   </html>
    
   

3. Create a virtual directory from Microsoft Internet Service Manager with read and execute access, and place all .asp and .asa files in that directory.

4. Create an HTML page from which to launch the oo4odemo.asp file. Add a link in the page as follows:

   <a href="/<your_path>/OO4ODEMO.ASP">This link launches the demo!</a>
   

5. Load the page in a web browser and click the link to the demonstration.

6. Enter a query, such as 'SELECT * FROM EMP', in the SQL SELECT Query field, and select the Submit Query button. Do not include a semicolon (;) at the end of the query.

   
   Description of the illustration iissamp.gif
   
   

Using Oracle Objects for OLE Automation with Excel

This sample shows how to insert Oracle data into an Excel worksheet.

To use OLE Automation with Microsoft Excel to insert Oracle data into a worksheet, perform the following steps:

1. Start Excel and create a new worksheet.

2. Use the Macro options in the Tools menu to create and edit new macros for manipulating the Oracle data.

   
   Description of the illustration exmacros.gif
   
   

3. Enter Visual Basic code for macros to create and access an Oracle dynaset, such as the following EmpData() and ClearData() procedures (macros):

   Sub EmpData() 
    
   'Declare variables 
   Dim OraSession As OraSession 
   Dim OraDatabase As OraDatabase 
   Dim EmpDynaset As OraDynaset 
   Dim flds() As OraField 
   Dim fldcount As Integer 
     Set OraSession = CreateObject("OracleInProcServer.XOraSession") 
     Set OraDatabase = OraSession.OpenDatabase("ExampleDB", "scott/tiger", 0&)  
     Set EmpDynaset = OraDatabase.CreateDynaset("select * from emp", 0&) 
     Range("A1:H15").Select 
     Selection.ClearContents 
    
      'Declare and create an object for each column. 
      'This will reduce objects references and speed up your application.  
   fldcount = EmpDynaset.Fields.Count 
   ReDim flds(0 To fldcount - 1) 
   For Colnum = 0 To fldcount - 1 
     Set flds(Colnum) = EmpDynaset.Fields(Colnum) 
   Next 
    
   'Insert Column Headings 
   For Colnum = 0 To EmpDynaset.Fields.Count - 1 
     ActiveSheet.Cells(1, Colnum + 1) = flds(Colnum).Name 
   Next 
    
   'Display Data 
   For Rownum = 2 To EmpDynaset.RecordCount + 1 
     For Colnum = 0 To fldcount - 1 
       ActiveSheet.Cells(Rownum, Colnum + 1) = flds(Colnum).Value 
     Next 
     EmpDynaset.MoveNext 
   Next 
   
   Range("A1:A1").Select
    
   End Sub 
   
   Sub ClearData() 
     Range("A1:H15").Select 
     Selection.ClearContents 
     Range("A1:A1").Select 
   End Sub 
   

4. Assign the procedures (macros) that were created, such as EmpData() and ClearData(), to command buttons in the worksheet for easy access. When you select the buttons, you can clear and refresh the data in the worksheet. In the following screenshot, ClearData() is assigned to the Clear button and EmpData() is assigned to the Refresh button.

   
   Description of the illustration exsheet.gif
   
   

Using Microsoft C++

For details about Oracle Objects for OLE with Visual C++, see Oracle Objects for OLE C++ Class Library Developer's Guide, available as online help.

Using Oracle Data Control with Visual Basic

Oracle Data Control, when refreshed, automatically creates a client (if needed), session, database, and dynaset. For a basic application, little or no code is required.

This section shows two ways to set the properties of Oracle Data Control:

• Using the Visual Basic Properties window

• Programming the properties

Using the Oracle Data Control with MS Visual C++

This example shows how to create a basic Win32 Application with Oracle Data Control using MS Visual C++. This example assumes that both the Oracle data and DB Grid controls were registered on the system.

1. Start the Microsoft Visual C++ program.

2. From the File Menu, select New.

3. In the Projects tab of the New Window, select MFC AppWizard.exe. Enter a project name, such as OO4O, and determine the location of the project. Click OK.

4. In Step 1 of the MFC AppWizard, select Dialog based application, then click Next.

5. In Step 2 of the wizard, make sure the ActiveX Controls box is checked; accept the defaults; and enter a title for the dialog box. Click Next.

6. In Step 3 of the wizard, accept the defaults. Click Next.

7. In Step 4, click Finish. At the New Project Information screen, click OK.

8. In the Project Workspace dialog box, select the ResourceView tab. Expand the Resources folder, then expand the Dialog folder.

9. Double-click the main project dialog box to edit the dialog box.

   Note: If you used OO4O as the project name, it is named IDD_OO4O_DIALOG.

10. Delete the default controls that are on the dialog box. Resize the dialog box to make it larger.

11. With the dialog box selected, click the right mouse button to display the menu. Select Properties from the menu. In the General tab of the Properties window, change the caption to Oracle Data Control Example. Close the Properties window.

12. With the dialog box selected, click the right mouse button to display the menu. Select Insert ActiveX Control... from the menu. Select ORADC Control in the window and then click OK.

    
    Description of the illustration oradcins.gif
    
    

13. Position the ORADC Control at the bottom of the dialog box. With the data control selected, click the right mouse button to display the menu. Select Properties from the menu.

14. In the General tab of the Properties window, change the ID to IDC_ ORADATACONTROL. Deselect the check mark for Visible so that the control is hidden when the application is run.

15. Display the All tab of the Properties window and set the following:

    Connect: scott/tiger 
    DatabaseName: exampledb 
    RecordSource: select * from emp 
    

    
    Description of the illustration oradcprp.gif
    
    

16. With the dialog box selected, click the right mouse button to display the menu. Select the Insert ActiveX control from the menu. Locate the DBGrid Control and click OK.

17. Position the DBGrid Control at the top of the dialog box and resize it. Display the properties for the control. In the All tab of the Properties window, set the DataSource property to Oracle Data Control (IDC_ORADATACONTROL). Accept the defaults for the other properties. These can be changed later.

18. From the File Menu, select Save All.

19. Build and Execute the project.

20. The DBGrid Control displays the records from the emp table as in the following illustration:

    
    Description of the illustration oradcemp.gif