Does any body know how to implement joins in GQL
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Thanks all. This is a lot of great information. I've learned a ton.
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Why isn't denormalization a real option? A lot of companies denormalize with
great success, including Google.
The thing about joins is this: they have to happen at some point in memory.
Datastore or local instance.
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Ikai Lan
Developer Programs Engineer, Google App Engine
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Because if you have denormalized data, then record updates can become
enormous. If someones address is denormalized into 1000 contact records,
then when the user updates their address the system has to go out to all of
the contact records and update them as well. And this gets multiplied by
William,
Could you explain how the update can be enormous with demoralized table? My
understanding is a flat table is easier to update that normalized one.
Thanks.
On Aug 5, 2011 1:36 PM, Ikai Lan (Google) ika...@google.com wrote:
Why isn't denormalization a real option? A lot of companies
I was trying to explain that with...
If someones address is denormalized into 1000 contact records, then when the
user updates their address the system has to go out to all of the contact
records and update them as well. And this gets multiplied by every complex
relationship that exists in
William,
You might want to go over this
http://static.googleusercontent.com/external_content/untrusted_dlcp/labs.google.com/en/us/papers/mapreduce-osdi04.pdf,
and come back again with any questions. Ikai and possibly others were
trying to convey to you that bigtable approach is more scalable
I didn't mean to suggest that.
Yes, a fanout is potentially bad, but the problem with the normalized
approach is that you equally optimize for reads and writes. In the address
book example, I update my address book about 1 time every 3 years. I read my
address book 20 times a day. I think it's
As far as managing complex data relationships, I don't think such a set of
practices exists. What I can and should do (once I get some time) is publish
some case studies about how we have persisted data in some cases. True,
denormalizing data often requires you to think a little bit, but that's
Date: Fri, Aug 5, 2011 3:13 pm
Subject: [appengine-java] Joins!
To: google-appengine-java@googlegroups.com
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On Fri, Aug 5, 2011 at 11:45 AM, William Levesque
billleves...@gmail.com wrote:
But is Google's position that all data should be denormalized?
I don't think anyone would say that. I wrote up my thoughts around
this subject here:
Greetings
I am trying to figure out a best-practice for avoiding the use of
joins. So far, it isn't going too well so here I am asking if anyone
is up for sharing their experience or linking to the reference I
failed to find. :)
An example of my requirement is this:
We have two classes:
Person
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