I'm using an invoicing/line items scenario. There is also another file for booking of equipment, which may or may not turn into an invoice later on. It's line items file is virtually identical to the invoicing line items file. So the question is, can't i just use the same line items file for two master files? There would be a few redundant fields in each record, depending on which master file was used to create the child record, but that shouldn't be a problem. The relational key should be enough to keep these records separate, shouldn't it? Seems to me that it would make importing easier and one less file to manage.

It is certainly possible. I do that with a Notes file. Many of my objects support the addition of any number of arbitrary dated notes. Rather than numerous files, I implemented this with one Notes file; each record has four fields, ID, Date, User, and the Note text. The ID is the ID of the record it corresponds to prefixed by the filename.

This works great when you primarily access the child file from the various master files. Accessing the master files from the child file would be kludgy and not particularly extensible... but possible.

that's great - thanks! i don't need to navigate backwards, so that's not an issue. nice to be able to get away with one less file - i'm already up to something like 35!