Use the TableDataBackupExtension to specify the file extension used by the engine for backup copies of the physical data file that makes up part of a logical DBISAM table. Backup files are created when altering the structure of a table or optimizing the table. The default value is ".dbk". Be sure to always include the filename extension separator (.) when specifying the file extension.
This property cannot be set while the engine is active and the TDBISAMEngine Active property is True.