You can't prevent them from messing with the table, but you could detect such modifications by adding a control field. The control field is updated everytime a field is modified in the current record or when adding a new record. You could use some control algorithm like a CRC to update the field. When reading a record, you compute the CRC (or other algorithm) and if that CRC don't match the control field, then the record was altered by an outside party (or is a bug...)

Another option would be to encrypt the data.

The downside of these approach is that they will slow down the application to some degree and the algorithm used for the control field could be found by the other party.

My personal recommendation if privacy is a concern, is to use a more secure database like MSDE or SQL Server.

HTH

>Is there any way to protect free tables from adding/changing records from external programs? I ask this because we have a application where there are some external companies who are adding and changing records in our software applications.