My database has nothing to do with numbers or prices. It basicly gathers text data for clients and displays related texts. No need for reports or summary fields. Lots of relationhips to relate the different types of text. I am considering separtation as follows and am writing this to see if I got it right: Ui file with scripts, relationships and the only fields are those that act as the match fields for the relationships to other files and data file (eg clinet number), and the Data file with lost of fields, value lists, calc fields.

I guess tha calc fields could be in the UI (eg: expressing the digit only number field for phone as (AC) XXX-XXXX format...) could be in either of the two files. I don't see the reason for the separate buisiness logic file. If the purpose of separation is to facilitate upgrades without tampering with data, the UI and BL could be together, is this not correct?

The Data file will need some scripts or am I wrong. Print lists or data, make new records, or is all this done via the relationship?

Is the List view possible (without a portal) if the data is not in the UI?

Thanks for all input and words of wisdom (Where's my pepcid?)

In the 3 file model the Data file contains the data only . The BR file contains calculations and relationships & scripts required to support them. It is also the file used for reports. And the Interface file has no tables, just layouts, relationships, scripts.

Phone numbers are text fields. I would use an auto-enter by calculation for formatting them in the data file.

There is nothing that would prohibit you from using a single file for both Interface and BR. Some prefer to put the calculations in the data file.