OneDbf:AddNtx(cName,cFile,cKey,lUnique,lUser): public: return true
  Index definition for this database is added.

  Parameter description:
  ~~~~~~~~~~~~~~~~~~~~~~
  cName: character: no default
   Menu item name for activating of this index file (SET ORDER).

  cFile: character: no default
   Index file name.

  cKey: character: no default
   Key expression for this index file.

  lUnique: logical: default is false
   Sets the index to be "unique".

  lUser: logical: default is false
   Sets the index to be user created when running the program.