Ben,
With non-relational databases like appengine's datastore you need to
create data based on the way you will query it rather than the way you
want to store it.
In your case it looks like you would need to create a model to store
the data you want to query (essentially an index that you manage). A
model something like the following might work.
PeopleOwnItemsIndex {
person (reference to the person owning the items/people)
owner (reference to the person owning the item)
item (reference to the item owned)
}
You'll be querying on the person field so the query will need to go in
your datastore-indexes.xml or index.yaml
When you change owners or add items you'll need to update the data for
this model. If you want to consolidate models you could also get only
your own items by creating an index on person+owner and query it with
person = me, owner = me. That would be instead of using PersonOwnItem,
but the difference would be you would have a record for each person
that can see the item rather than only one for the person owning the
item.
Ian
On Sun, Jun 13, 2010 at 4:10 AM, Ben Woodhead <[email protected]> wrote:
> Hello Everybody,
>
> I am very comfortable with SQL and relational databases and I am
> trying to wrap my head around GAE. Below is an example of how I would
> tackle my problem in SQL and it would be really great if someone could
> give me some hints on how to accomplish something similar in GAE. Its
> basically a hierarchy of ownership.
>
> The 2 base tables:
>
> table People {
> int personId;
> string name;
> }
>
> table items {
> int itemId;
> string itemName;
> }
>
> The 2 relational tables:
> table PeopleOwnPeople {
> int ownersId;
> int personId;
> }
>
> table PeopleOwnItems {
> int personId;
> int itemId;
> }
>
> So now that we have a basic structure I can start to explain the idea
> or problem. I want to be able to search for all items owned by me and
> the people i own:
>
> select items.* from Items, PeopleOwnPeople, PeopleOwnItems where
> (PeopleOwnPeople.ownersId=234 and
> PeopleOwnPeople.personId=PeopleownItems.personId) or
> PeopleOwnItems.personId = 234 ;
>
> I am looking to use GWT as my frontend to this project so I am likely
> going to be using Java for the backend but that isn't set in stone
> yet.
>
> Thanks any and all help.
> Ben
>
> --
> You received this message because you are subscribed to the Google Groups
> "Google App Engine" group.
> To post to this group, send email to [email protected].
> To unsubscribe from this group, send email to
> [email protected].
> For more options, visit this group at
> http://groups.google.com/group/google-appengine?hl=en.
>
>
--
=======================================
株式会社ビープラウド イアン・ルイス
〒150-0021
東京都渋谷区恵比寿西2-3-2 NSビル6階
email: [email protected]
TEL:03-6416-9836
FAX:03-6416-9837
http://www.beproud.jp/
=======================================
--
You received this message because you are subscribed to the Google Groups
"Google App Engine" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/google-appengine?hl=en.
