File capabilities are used to control which input/output operations are allowed for a database file independent of database file authority.
When you create a physical file, you can specify if the file is update-capable and delete-capable by using the ALWUPD and ALWDLT parameters on the Create Physical File (CRTPF) and Create Source Physical File (CRTSRCPF) commands. By creating a file that is not update-capable and not delete-capable, you can effectively enforce an environment where data cannot be changed or deleted from a file once the data is written.
File capabilities cannot be explicitly set for logical files. The file capabilities of a logical file are determined by the file capabilities of the physical files it is based on.
You cannot change file capabilities after the file is created. You must delete the file then recreate it with the desired capability. The Display File Description (DSPFD) command can be used to determine the capabilities of a file.