4 Replies Latest reply on Feb 10, 2012 1:25 AM by Ytzen Terpstra

Online vs Offline issues in HTML5

Ytzen Terpstra Jan 31, 2012 6:46 AM

We are doing some prototyping for an offline web application using HTML5. For local data storage we are experimenting with the HTML5 WebSQL feature, but we are encountering some difficulties.

We tried using separate tabs or frames that access the database, but this resulted in hang-ups and crashes. It is not an absolute requirement that this should work, but are you familiar with such behaviour and do you know a solution to prevent these crashes?

Storing larger amounts of data is also an issue. For example: storing ‘only’ 1000 records in an empty table (with about 10 columns) took 60 seconds on a Motorola Xoom. Retrieving the records is much faster, so we were curious whether storing data can be made faster. Currently we are storing each record separately using a “INSERT OR REPLACE INTO” query.

If someone has some advice on how to adress these issues, if possible, we would be very greatful.

Thanx in advance,

Ytzen Terpstra

ViaData Automatisering BV

The Netherlands

www.viadata.nl

Re: Online vs Offline issues in HTML5

Darryn Campbell Jan 31, 2012 4:15 PM (in response to Ytzen Terpstra)

Hi,

At the moment you may get better assistance posting on the RhoMobile google group for RhoMobile questions: http://groups.google.com/group/rhomobile?pli=1

As we align the two products we will also be aligning our support.

Thanks.
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- Re: Online vs Offline issues in HTML5
  
  Ytzen Terpstra Feb 10, 2012 1:23 AM (in response to Darryn Campbell)
  
  Thanks for your advice although I'm not quite sure about what I have to think of this advice. I've been visiting the Motorola AppForum in Barcelona last november. A lot of attention was focused on the introduction and use of RhoElements. Everything you need to know about RhoElements (but were afraid to ask..) could be found on the launchpad site (demos, FAQ, discussions, etcetera) was said. First question I ask and I'm rerouted to the Google Group, that's a bit awkward I find.
  
  Nevertheless, thanks for your advice.
  
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Re: Online vs Offline issues in HTML5

Njål Stabell Feb 9, 2012 8:35 AM (in response to Ytzen Terpstra)

Hi,
The trick is using union select as a workaround to single inserts for SqlLite.
I posted a codesample to another thread on this forum:

https://motorola-dev.hosted.jivesoftware.com/thread/1374

Hope it helps.. this approach saved us in our last customer project
Customer success story here (with single inserts it wouldn't have been a success)
http://neptune-software.com/portfolio/expert-3/
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- Re: Online vs Offline issues in HTML5
  
  Ytzen Terpstra Feb 10, 2012 1:25 AM (in response to Njål Stabell)
  
  Hi Njal,
  
  Thanks for your help. We'll try your solution right away and of course let you know if this can do the trick for us.
  
  Ytzen
  
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