PRB: SqlBCPColumnFormat in VBSQL.OCX Fails

• Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 16-bit and 32-bit, for Windows, version 4.0

SYMPTOMS

When using the VBSQL function SqlBCPColumnFormat, you may receive various errors including:

   "Bad DLL Calling Convention"

CAUSE

The declaration for calling the SqlBCPColumnFormat function requires an array of a structure to obtain the necessary information about the columns to be copied. The structure includes a non-numeric variable length member. Visual Basic version 4.0 does not provide the capability to pass arrays of structures with variable length members to called functions.

RESOLUTION

Use the related functions SqlBCPColumns and SqlBCPColfmt instead.

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The Visual Basic Library for SQL Server (VBSQL.OCX) custom control file and supporting information documents allow direct use of functions built-in to Microsoft SQL Server including bulk copy of information to and from SQL Server data sources.

The function SqlBCPColumnFormat is used to identify the columns to be copied in the bulk copy process. Detailed column properties such as data types, column length, column delimiters, etc. are defined earlier in an array of the BCPColData structure. The following is an example function call:

   Result = SqlBCPColumnFormat(<Connection>, <Column Data>, <NumColumns>)

        <Column Data> is the definition of the columns being copied.
              This information is an array of a structure BCPColData
              as defined in the declaration of the function. This
              structure has one non-numeric member.
        <NumColumns> is the number of column in the bulk copy.

A workaround is to use the functions SqlBCPColumns and SqlBCPColfmt, which provide the same functionality of describing the columns to be copied:

• SqlBCPColumns() identifies the number of columns to be copied.
• SqlBCPColfmt() is used once for each of the columns to be copied, and specifies the detailed column properties such as data type, maximum length, column delimiter, etc.

    Dim Connexion, Login, Result, RowsCopied As Long

    'Initialize connection to backend
    Login = SqlLogin()
    Result = SqlSetLUser(Login, <userid>)
    Result = SqlSetLPwd(Login, <password>)
    Result = SqlBCPSetL(Login, True)
    Connexion = SqlOpen(Login, <Data Source Name>)

    'Setup copy of Authors table in Pubs database
    '  to a text file c:\bulkcopy.txt
    Result = SqlBCPInit(Connexion, "pubs..authors", _
          "c:\bulkcopy.txt", "c:\bcperr1.txt", DBOUT&)

    '4 columns will be copied
       Result = SqlBCPColumns(Connexion, 4)

    'Format each column, see help topics for details
       Result = SqlBCPColfmt(Connexion, 1, 0, 0, -1, vbTab, 1, 1)
       Result = SqlBCPColfmt(Connexion, 2, 0, 0, -1, vbTab, 1, 2)
       Result = SqlBCPColfmt(Connexion, 3, 0, 0, -1, vbTab, 1, 3)
       Result = SqlBCPColfmt(Connexion, 4, 0, 0, -1, vbCRLF, 2, 4)

    'Execute the bulk copy
       Result = SqlBCPExec(Connexion, RowsCopied)
       MsgBox RowsCopied & " rows were copied"

    'Close connection
       SqlClose Connexion
       SqlExit

• Microsoft SQL Server Programmer's Toolkit for Visual Basic.
• "Hitchhikers Guide to Visual Basic and SQL Server" as described in the references. The files are included on the accompanying CD-ROM.
• Microsoft Developers Network (MSDN).

REFERENCES

Building Client/Server Applications Using Visual Basic, Chapter 8, Pages 147-148

Hitchhiker's Guide to Visual Basic and SQL Server, 4th Ed., Chapter 32, by William Vaughn. ISBN 1-55615-906-4

Keywords          : APrgDataOther IAPThird PrgCtrlsCus VB4ALL VB4WIN
Version           : WINDOWS:4.0
Platform          : WINDOWS
Issue type        : kbprb