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Q176830: HOWTO: Create a Connection Programmatically

Article: Q176830
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:3.0b; WINDOWS:2.5,3.0,3.0b,5.0,5.0a,6.0
Operating System(s): 
Keyword(s): KbClientServer kbDatabase kbServer kbvfp300 kbvfp500 kbvfp600 kbMDAC250
Last Modified: 22-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0 
- Microsoft Visual FoxPro for Macintosh, version 3.0b 
- Microsoft Data Access Components version 2.5 
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SUMMARY
=======

Under some circumstances, you may need to modify the properties of a connection
at run time. This article describes each of the properties and the default
values of a connection. The sample code illustrates how to create a connection
and use the DBSETPROP() function to set the properties of a connection
programmatically.

MORE INFORMATION
================

The following table indicates the data types and default values associated with
each of the properties of a connection.

  Property       Connection Designer Label    Data Type   Default Value
  ---------------------------------------------------------------------

  DispLogin        Display Login               Numeric        1
  Asynchronous     Asynchronous Execution      Logical        .F.
  DispWarnings     Display Warnings            Logical        .F.
  BatchMode        Batch Processing            Logical        .T.
  Transactions     Automatic Transactions      Numeric        1
  PacketSize       Packet Size                 Numeric        4096
  Comment                                      Character      ''
  ConnectTimeOut   Connection (sec)            Numeric        15
  IdleTimeOut      Idle (min)                  Numeric        3
  QueryTimeOut     Query (sec)                 Numeric        3
  WaitTime         Wait Time (ms)              Numeric        100

The sample code below creates and modifies the properties of a connection:

     *Begin code
     LOCAL lcconnstring, lcconname, lnconnections, lbconnexists
     lcconnstring    =  "'DSN=PUBS;DATABASE=pubs;UID=sa;PWD='"
     lcconnname      =   "VFPCONN"
     lnconnections   =   0
     lbconnexists    =   .F.
     IF !FILE('VFPCONN.DBC')
     CLOSE DATA ALL
     CREATE DATABASE VFPCONN
     ELSE
     OPEN DATABASE VFPCONN
     ENDIF
     lnconnections=ADBOBJECTS(CONNECTS,'CONNECTION')
     IF lnconnections>0
     FOR i=1 TO ALEN(CONNECTS,1)
     IF UPPER(CONNECTS[i])=lcconnname
     lbconnexists=.T.
     EXIT
     ENDIF
     NEXT
     ENDIF
     IF !lbconnexists
     CREATE CONNECTION &lcconnname CONNSTRING (lcconnstring)
     ENDIF
     * Set connection properties to custom values.
     =DBSETPROP('VFPCONN','Connection','DispLogin', 3)
     =DBSETPROP('VFPCONN','Connection','Asynchronous', .T.)
     =DBSETPROP('VFPCONN','Connection','DispWarnings', .T.)
     =DBSETPROP('VFPCONN','Connection','BatchMode', .F.)
     =DBSETPROP('VFPCONN','Connection','Transactions', 2)
     =DBSETPROP('VFPCONN','Connection','PacketSize',8192)
     =DBSETPROP('VFPCONN','Connection','Comment', 'Comment Added')
     =DBSETPROP('VFPCONN','Connection','ConnectTimeOut', 10)
     =DBSETPROP('VFPCONN','Connection','IdleTimeOut', 0)
     =DBSETPROP('VFPCONN','Connection','QueryTimeOut', 0)
     =DBSETPROP('VFPCONN','Connection','WaitTime',150)
     MODI CONNECTION VFPCONN
     RETURN
     *End code.

After running the program code, a dialog appears titled "Connection
Designer-VPFCONN." Click the Verify Connection button and a message indicating
the connection was successful should appear.

NOTE: In order to use the connection, an ODBC Data source matching the Data
source name specified in the connection string must exist.

If the ODBC Data source does not exist, the following ODBC error message is
returned:

  Connectivity error [Microsoft][ODBC Driver Manager] Data source name not
  found and no default driver specified.

REFERENCES
==========

For additional information, please see the following article(s) in the Microsoft
Knowledge Base:

  Q137445 How to Display View and Connection Properties

  Q132231 Properties You can Access with SQLGETPROP()

Visual FoxPro Help, version 4.00.950; search on: "DBSETPROP()"

Additional query words:

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Keywords          : KbClientServer kbDatabase kbServer kbvfp300 kbvfp500 kbvfp600 kbMDAC250 
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbMDACSearch kbMDAC250 kbVFP300bMac kbVFP300 kbVFP300b kbVFP500 kbVFP600 kbVFP500a
Version           : MACINTOSH:3.0b; WINDOWS:2.5,3.0,3.0b,5.0,5.0a,6.0
Issue type        : kbhowto

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