You can access Structured File Server (SFS), DB2, or Oracle files with the COBOL-IT compiler through the EXTFH compatible function. After preparing the environment, the routines that you follow for accessing data are same for all files of same type. Difference between a standard COBOL I/O and an I/O to an Structured File Server (SFS) file, DB2 file, or Oracle file using EXTFH is not evident.
An External File Handler (EXTFH)-compatible function is supported in the COBOL-IT software, and by the External File Handler (EXTFH) code on the DB2, SFS, and Oracle file system managers. The External File Handler (EXTFH) interface generates output files if they do not exist. You need to open existing file for output in the extended mode, to avoid their contents being erased.