SAMPLE: VBCobSQL.exe - Mixed-Language Apps (VB, COBOL, SQL)

VBCobSQL.exe demonstrates a mixed-language (Microsoft Visual Basic, COBOL, and ESQL) application.

You can use Microsoft(R) Visual Basic(TM), Microsoft COBOL, and Microsoft SQL Server to build full-featured client-server applications that use the strengths of each product. Visual Basic creates the graphical user interface. Subroutine calls are made in the Basic code to COBOL dynamic-link libraries (DLLs). The COBOL DLL contains Embedded SQL (ESQL) to request the necessary data from the SQL Server. The COBOL DLL manipulates the retrieved data as required, then passes the data back to Visual Basic. In other words, Visual Basic is the graphical front-end and COBOL DLL is the back-end of the client application.

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VBCOBSQL uses the PUBS database from the SQL Server package. The demo makes several queries to the PUBS database, such as Author Search and List Publications in a Category. It also allows you to insert and delete authors and add new publications to the database.

To build VBCOBSQL, you will need Visual Basic version 2.0 Professional Edition, Microsoft COBOL version 5.0 or Micro Focus(R) COBOL version 3.0, and Embedded SQL Toolkit for COBOL.

In Visual Basic, load the VBCOBDEM.MAK project and build an .EXE file for the application. Before building the COBOL DLL that accesses SQL Server, make sure that your build environment is set up to build COBOL/SQL Server applications. Set the LIB environment variable to include the drive and path of the following files:

• LCOBOLW.LIB (supplied with the COBOL compiler)
• COBW.LIB (supplied with the COBOL compiler)
• SQLAKW.LIB (supplied with Embedded SQL for COBOL)
• W3DBLIB.DLL (supplied with Embedded SQL for COBOL)

You also need the object file, CBLWINA.OBJ, supplied with the COBOL compiler. You must specify "Mixed Language Support" when you install this file from the COBOL disks.

Next, edit the VBCOBSQL.DIR directives file to use your own server, database, user ID, and password. There are two ways to build the DLL:

• Run COBC.BAT and COBL.BAT, in that order. The first batch file compiles the DLL and the second links it. VBCOBSQL.DLL will be created.
• Build the DLL using Programmer's WorkBench (PWB). This sample includes the VBCOBSQL.MAK make file to allow you to build with PWB.

Make sure that this DLL is in your current directory or in your PATH. For more information on building DLLs, see "COBOL Programming for Windows," Chapter 2 (Building Dynamic Link Libraries) included with Microsoft COBOL or the Micro Focus(R) COBOL User's Guide.

Before running the demo, make sure that the following files are in your current directory or in your PATH:

• SQLAKW.DLL (provided with Embedded SQL toolkit for COBOL)
• W3DBLIB.DLL (provided with Embedded SQL toolkit for COBOL)
• DBNMP3.DLL (provided with Embedded SQL toolkit for COBOL)
• CBLWIN.DLL (provided with the COBOL compiler)
• CBLSSEG.DLL (provided with the COBOL compiler)
• VBRUN200.DLL (provided with Visual Basic version 2.0)

To run the demo, run the executable file you created in Visual Basic. You can also run the demo interactively in Visual Basic. In the login screen, fill in the fields required to log into the PUBS database. If the login is successful, you will be in the demo. You can then select SQL options from the menu to perform the search/update operations. Use the Help menu items to get more information on using the demo and building mixed-language client-server applications.

VBCOBSQL is a companion application for the "Building VB/COBOL/ESQL Mixed-Language Applications" technical article on the Microsoft Developer Network CD.