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Re: Indexed Database API

From: Jeremy Orlow <jorlow@chromium.org>
Date: Fri, 4 Mar 2011 12:03:54 -0800
Message-ID: <AANLkTimq-+QTKc4EGo2vRQJdeqhOMso3_XyT5QexQoko@mail.gmail.com>
To: Ben Dilts <ben@lucidchart.com>
Cc: public-webapps@w3.org
On Fri, Mar 4, 2011 at 11:33 AM, Ben Dilts <ben@lucidchart.com> wrote:

> Jeremy,
>
> Thanks for the reply!  However, my indices are not typically unique,
> contiguous numbers.  For example, I have an index on an item's "saved" date,
> as a MySQL-style date/time string.  These dates are not necessarily unique,
> and are certainly not contiguous.  So if a user is currently viewing the
> first 20 items in this object store, and would like to jump to page 5 (items
> 81-100), how would I go about that?  I don't know what key value is in the
> 81st position in the index.  In fact, the key value in position 81 may also
> occupy positions 80 and 82--if I skip to that key value, I may end up in a
> slightly wrong place.
>

If you're jumping beyond what you've already looked at, then yeah...the
current API is probably not sufficient.

I wouldn't mind adding an option to openCursor to start the cursor some
number of items forward of the first element in the key range.  I also
wouldn't mind adding some sort of "jumpForward" method to IDBCursor.

J


> On Fri, Mar 4, 2011 at 11:33 AM, Jeremy Orlow <jorlow@chromium.org> wrote:
>
>> On Tue, Mar 1, 2011 at 11:02 PM, Ben Dilts <ben@lucidchart.com> wrote:
>>
>>> Why is there no mechanism for paging results, a la SQL's "limit"?  If I
>>> want entries in positions 140-159 from an index, I have to call continue()
>>> on a cursor 139 times, which in turn unserializes 139 objects from my store
>>> that I don't care about, which in FF4 is making a lookup in IndexedDB
>>> sometimes take many seconds for even a few records.  It makes no sense--am I
>>> just missing something in the spec?
>>
>>
>> Just use cursor.continue() with a key parameter to skip the cursor ahead
>> to where you care about.
>>
>> J
>>
>
>
Received on Friday, 4 March 2011 20:04:45 GMT

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