Hi Thomas,
What FDS is going to use those
relationships for is ensuring that it keeps track of items on the client for
consistency and attempts to avoid having the same item twice (everything is
kept in sync). In this case you would define the relationship in the metadata
as many-to-many I believe. It will be up to your assembler to actually update the
database tables, so you are in complete control of that aspect. FDS does not
do any database manipulation, it simply sends you change objects which indicate
the updates the client wants to make. If the client makes a mistake, your
assembler can take care of notifying the app of an error.
HTH,
Matt
From: flexcoders@yahoogroups.com [mailto:flexcoders@yahoogroups.com] On Behalf Of Thomas Rühl
Sent: Wednesday, August 16, 2006
7:03 AM
To: flexcoders@yahoogroups.com
Subject: [flexcoders] [Flex Data
Services] Managed associations / DB abstraction ?
Hello flexcoders,
following the «Managed Associations» approach, I just encountered a
question.
Please assume this:
I have a set of entities created in my database, i.e. Employee and
Company - to stick with the examples. In contradiction to the examples,
assume that they relate in a n-m manner, meaning one company can have
any number employees and one employee can have any number of companies.
For that, to come up with a good database layout, I'd need to design a
corresponding relation in the database - «Employee», «Company» and
«EmployeeHasCompany» (the ladder one is the n-m relation - it holds
foreign keys to each, employee and company).
Let's say all of that is set so far and the application's requirements
demand the database level cohesion of data and for that, require the
table structure to be like I pointed out.
Now here's some random thoughts... How do I model that for use with the
Flex Data Services? I know, there's some destination properties
(one-to-one, one-to-many, ...) on which basis FDS manages data supply.
Isn't that situation not only redundant but also risky to use? I'm
thinking of transactions, date consistency and else... And how do I
update the EmployeeHasCompany relation with new data? Is it like I need
to trust FDS to do the right things? I'm afraid of losing control here.
So all in all, I think, my question is how to transfer the database
model accordingly to the FDS confuguration? Or maybe I'm just off the
track here.
Cheers, Thomas
Thomas Rühl
Design, Programming & Concepts
akitogo OHG
Hanauer Landstrasse 188
60314 Frankfurt
Telefon +49 (0) 69 800 69 445
Fax +49 (0) 69 800 69 449
Mobil +49 (0) 179 750 75 87
E-Mail thomas.ruehl@akitogo.com
Web http://www.akitogo.com
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