On Dec 26, 2009, at 12:48 PM, Helen W. Lee wrote:

> I'm still hoping somebody can point me to something which can help
> me get my brain around the concept of "tables" in FMP10. As I read
> the current discussions on this list I see a faint glimmer of light
> over them and I do remember when FMP7 came out there was a lot of
> discussion over the "new method" of handling data it presented but
> since I wasn't planning to upgrade, I didn't pay much attention -
> except to assert to myself that I didn't want to go that route. Now
> I have to, so need to get my brain around the concept, as I'm sure
> the new system is most likely more efficient that my antique system
> is.

You've always been using tables, you just didn't know it. The real
abstraction comes with table occurrences, and perhaps this is where
you're getting tripped up (especially because the term 'table' is used
throughout the UI where they should be using 'table occurrence').

In previous versions of FileMaker, each file could have only one
table. Since a file had only one table,it didn't make sense to give
that table a name separate from the file, therefore you had a file
called "Customers.fp5" that had the "Customers" table in it (in your
mind at least). And with only one table in the file, all of the
layouts in the file show records from that table (the layouts were
"attached" to that table but since there was only one table anyway, it
didn't make sense to add the concept of attaching a layout when there
were no "options" to choose from). And with all of the layouts
connected to that one table, all of the scripts in the file operated
on that one table as well.

The radical change in FMP 7 came with the introduction of table
occurrences and the relationships graph. Instead of tying layouts
directly to tables, FMP now ties layouts to table occurrences, which
can be thought of as an alias to a table. A table can have many such
aliases, and each serves as a distinct pointer back to the original
table. In FMP 6, with the one table model, all layouts shared the same
found set and sort order in a particular file. With FMP 7, layouts
could be attached to different table occurrences, and therefore they
could have different found sets and sort orders, EVEN IF those table
occurrences all pointed back to the same table.

So the addition of table occurrences (an "abstraction" for tables)
created a big shift in how FMP files worked. With the table now
abstracted by table occurrences, the next bit is multiple tables.
Having more than a single table in a file is no big thing now, because
we never deal with tables directly, only the table occurrences. So
where you would have your "Customers" table in a file called
"Customers.fp5" and your "Addresses" table in a file called
"Addresses.fp5", now you can put both tables into a single file (what
you call that file is up to you). On your relationships graph, you
would have one or more table occurrences for each table which would
allow layouts to show records from each table.

To further the power of the concept of table occurrences, they don't
even need to be for tables in the current file. Tables defined in
other files can be represented by table occurrences on a file's
relationship graph and layouts in the file can be attached to these
"foreign" table occurrences. Because of this, the concept of "files"
has gone from being all encompassing to having a more circumspect role.

For another take on this, I'd suggest reading the FMP 7 Key Concepts
white paper by Michael Harris (sorry, I don't have the link of hand
but you can search for it I'm sure).

> I'd also still love to know why the file extension is stuck at fp7
> instead of increasing with each new version of FMP.

The file extension thing is easy, since it's been this way since FMP 3
and hasn't changed since.

FileMaker Pro 3, 4, and 4.1 all shared the same file format which was
denoted by the extension '.fp3'
This meant a copy of FileMaker Pro 3 could open a file created in
FileMaker Pro 4.1, although new features added in FMP 4.1 things
wouldn't work properly in FMP 3.

When FMP 5 came out, the new features required them to change the file
format such that files created with FMP 5.0 could not be opened by FMP
4.1 or earlier. To enforce the idea, the changed the extension to
'.fp5' with the release of FMP 5. As with previous versions, FMP 5.5
and FMP 6.0 shared the same file extension and FMP 5.0 could open
files created by these later versions, with the same limitations as
mentioned before.

The same is true of FMP 7 and later. FMP 7, 8, 8.5, 9, and 10 all
share the same file format (and hence file extension) as previous
versions. As with previous versions, FMP 7 can open a file created in
FMP 10, however new features added in subsequent versions will not
work properly when opened with an older version.

Cheers,
-corn


Cornelius Walker
The Proof Group
http://proofgroup.com/


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