Deleting a Record

Deleting a Record

Question:
I am currently building a VB application that needs to delete records in a .dbf field. The connection to the database is established through ADO by using a DSN. Currently, when I attempt to delete a record (using SQL’s delete), the record is simply marked to be deleted, but is not deleted.

How do I delete the record?

Answer:
Visual FoxPro has a command called PACK that removes records marked as “deleted” from the DBF and rebuilds the indices on the table. It requires exclusive use of the table.

There are two approaches for calling this command. First, you could create a VFP COM object that has a method called Pack with a parameter of what file (with full path) to pack. You could then instantiate this object from your application and call the Pack method.

Create a project with the following program and compile it as a DLL:

 DEFINE CLASS VFPDBFUtility AS CUSTOM OLEPUBLICPROC PackLPARAMETERS tcTableFile   LOCAL llError   llError =.F.   ON ERROR llError=.T.   USE (tcTableName) EXCLUSIVE   IF llError      RETURN .F.   ENDIF   PACK   USE   ON ERROR   *-- Return .T. if no error, .F. if error occurred   RETURN !llErrorENDPROCENDDEFINE

The other approach would be to instantiate VFP as an automation server and use the DoCmd method to run the commands. This requires that VFP is installed on the server:

 lcFile = 'C:mydbf.dbf'oVFP = CREATEOBJECT('visualfoxpro.application')oVFP.DoCmd('USE '&& lcFile &&' EXCLUSIVE')oVFP.DoCmd('PACK')oVFP.DoCmd('USE')
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