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POHow to iterate through a joined table with multiple results?
 

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  1. POHow to iterate through a joined table with multiple results?
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    <p>I have 3 tables, <code>USER</code>, <code>ENTRY</code> (for entered products, not necessary to create a PRODUCT table), and <code>USER_COLLECTION</code>, which is a table inbetween <code>USER</code> and <code>ENTRY</code>, because an entry can have multiple users.</p> <p>Basically:</p> <p>User = <code>USERID | USER_NAME</code></p> <p>Entry = <code>ENTRYID | ENTRY_NAME | ENTRYPRICE | ENTRY_DATE</code></p> <p>Collection = <code>COLLECTIONID | ENTRYID | USERID</code></p> <p>I have a table with users that persist throughout the project. They can create entries (which is usually some kind of product with a price) and they can link multiple users to a certain entry (which can be selected from a list, hence the users persist throughout the project).</p> <p>So for instance, my tables look like this:</p> <pre><code>User -------------------------- user_id | user_name -------------------------- 1 | 'FOO' 2 | 'BAR' 3 | 'FOOBAR' ENTRY ----------------------------------------------------------------------- entryid | entry_name | entry_price | entry_date ----------------------------------------------------------------------- 0 | 'Banana' | 2.50 | 12/12/2012 COLLECTION --------------------------------------- collectionid | entryid | userid ---------------------------------------- 0 | 1 | 1 1 | 1 | 2 2 | 1 | 3 </code></pre> <p>I have a Banana, with a price of 2.50 and 3 users linked to it, Foo, Bar and Foobar.</p> <p>Now, I want to use this in my app and get the data; except I don't know where to start. I tried selecting the entry data, using that id to loop through the collection data, but that would mean I have two cursors open and it wouldn't work. Tried creating a join but I couldn't really make a good one, mainly because:</p> <pre><code>JOIN --------------------------------------- collectionid | entryname | username ---------------------------------------- 0 | Banana | FOO 1 | Banana | BAR 2 | Banana | FOOBAR </code></pre> <p>I can't iterate through this, because I would create multiple of the same entry objects in my Android code...</p> <p>Hope I'm being clear on this.</p> <pre><code>if (cursor2.moveToFirst()) { do { Item i = new Item(&lt;GET STUFF FROM CURSOR&gt;); i.addUser(new Person(&lt;GET STUFF FROM CURSOR&gt;))); Log.d("TAG", i.getUsersPaying().size() + ""); } while (cursor2.moveToNext()); } </code></pre> <p>If I use this, I create mulitple instances of Item i. They'll all be Banana, whilst I should only have 1 item Banana, with multiple users added to it.</p>
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      1. POHow to iterate through a joined table with multiple results?
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    1. COwhy is `COLLECTION.collectionId` not incrementing? shouldn't it autoincrement?
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      1. USDavid M
    2. COError on my part. Editing now
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    3. COyour join data looks like i would expect. it says that Foo, Bar, and Foobar have (bought?) a Banana. a cursor would hit each row in turn and you process that row. what do you expect to see? (maybe i'm missing something here)
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