calculation contexts

[rdhaden]

OK, I'm trying, but I don't get this context thing in relation to calculations. I guess really I don't get the whole relationship model in FM7. Here are my questions:

If I have a field that calculates based on fields in the same record, then what's the context?

What's the difference between a table and a table occurrence? Isn't a table occurrence exactly what it says, an occurrence of your table in the relationship graph? Then why do the table occurrences have names, each different from the name of the table itself? Aren't relationships between tables, not between table occurrences? If so, why do the table occurrences have names instead of the relationships?

What's the difference between the context of a calculation and the relationship that specifies the related fields in that calculation?

Anybody have any helpful resources? Call me crazy, but Filemaker Help's entry on defining calculations didn't clear it up for me.

[transpower]

1. the table is the context (if you have multiple table occurrences, then you can have multiple contexts to choose from)

2. table means base table (the original table you created); table occurrence is a copy of the base table displayed in the Relationship Graph to enable an additional relationship

3. the context is for the field you're calculating

4. see the discussion of these matters in Using FileMaker 7 by Lane, Bowers, Love, and Moyer

[rdhaden]

Thanks for the tip, I'll check it out.

It seems to me then that there is no such thing as FieldA = FieldB + FieldC. Now everything would have to be FieldA (in the context of TO1) = TO1::FieldB + TO1::FieldB.

I got Jonathan Stars "Learn Filemaker Pro 7." Silly me, I thought I had to learn it before I could use it. If you look for the word "context" in the index, all you get is info about how you can right click for context menus.

[transpower]

Stars' book is for intermediate level programmers. The book by Lane, et. al., is for advanced programmers. I just finished it recently and learned a great deal, such as uses for the Last function (which is used by several forum members in today's posts). Using FileMaker 7 has a complete list of functions and script steps, with examples.

It's now considered good practice to use table references in field definitions, even when it's not strictly necessary.

[ptr]

"Using FileMaker 7 by Lane, Bowers, Love, and Moyer" Is this a text? Does it explain in detail the relational model in fM7 and buildinf complex reationships. I too purchased Star's book and found it did not help me to understand the new way of doing things in FM7

[transpower]

Yes.