The COBOL FD Importer tab is displayed in 'Updating FD from Source' mode. If you opened the COBOL FD Importer tab from the File menu, this mode is not enabled and you will be unable to perform the merge process with existing file definitions.
A further two tabs are displayed. The Items to Import tab displays the FDs found in the selected file, and the Messages tab contains output from the Schema Extractor process.
For each selected file definition, an additional Update... tab containing a merge editor is displayed. Each FD is compared with the original FD, and an attempt is made to auto-resolve each field in the record.
Details of the difference between the original and new field are displayed.
Once all unmatched fields are resolved, the Complete Merge for FD option becomes available.
The updated file definition is now displayed in the Catalog Explorer. The existing file definition is still available in the Catalog Explorer, but has (Previous) appended to its name, and any tables associated with the previous FD have 'OLD' appended to their name. You can delete this file definition if it is no longer required, but first you must delete any existing table definitions for that file definition.