On 8/5/06, Michael Babcock <[EMAIL PROTECTED]> wrote:
What steps do you take when preparing to migrate data stores from DBFs
to remote databases like SQL Server?
It sounds like you will not be executing a complete migration, but
rather having to synchronize a set of DBFs with a backend server for
some period of time. That's an app that needs to be written.
If you're switching some of your apps from DBFs to client-server,
you'll need to wedge the code in to do that. In previous gigs, I
overhauled data access to use a data manager (while still using DBFs)
and then wrote the equivalent functionality for the back-end server.
Switch then becomes a matter of flipping a setting. After debugging,
of course.
Obviously you try to minimize the
Fox-specific stuff, but are there a general set of guidelines you can
use to migrate free (non-dbc linked) tables?
Well, the only way to ensure your data will actually fit is to migrate
it. Anticipate longer than you imagine when you try to clean your
data. You'll find data overflow conditions, underflow conditions, bad
dates ("Oh, Indie! Bad Dates."), orphaned records, dirty data and
more. Data's got to be migrated in specific orders (lookup tables
first, then parents, then children) for PK-FK purposes. Turn off RI
while you do this, but expect turning it back on again will break
something.
If they were in a DBC, I
could see adding triggers to help "mirror" the data on the RDBMS until
you fully migrated over, but I don't think that's an option here, as
some tables are still used by a Fox 2.x app.
Nope, the best you can do is a timer-driven app (or scheduled app)
that checks LUPDATE() and diffs files. Will your synchronization be
only from DBF -> backend, or will it need to support two-way
synchronization?
--
Ted Roche
Ted Roche & Associates, LLC
http://www.tedroche.com
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