You can protect a data source from changes by including the READ parameter when issuing a USE command. A protected data source can be read by various tools and commands, but cannot be changed.
USE fileid READ END
Is any valid file specification for the operating system.
Restricts the data source to read-only access.
The following command protects the EMPLOYEE data source from modification.
USE EMPLOYEE.FOC READ END
USE EMPLOYEE READ END
USE /usr/mydata/employee.foc READ END