ISDBT()
 Determines if a memo file (.dbt) is present
------------------------------------------------------------------------------
 Syntax

     ISDBT() --> lPresent

 Returns

     ISDBT() returns .T., if a database has a memo file associated with it.

 Description

     ISDBT() determines if a database has a memo file associated with it, and
     allows you to compress that memo file.

 Example

     If the database has a memo file, the database is copied to minimize the
     memo file:

     USE DATA
     IF ISDBT()
        COPY TO TEMP
        CLOSE DATABASES
        DELETEFILE("DATA.DBF")
        DELETEFILE("DATA.DBT")
        RENAMEFILE("TEMP.DBF", "DATA.DBF")
        RENAMEFILE("TEMP.DBT", "DATA.DBT")
     ENDIF