Rob Tiffany's Windows Mobile Accelerator : SQL Server Compact

New Blog Site @ http://robtiffany.com

robtiffany — Wed, 23 Dec 2009 23:58:00 GMT

Hey everyone,

Just wanted to let you know that I'm continuing this blog over at robtiffany.com. I've finally decided to make better use of my personal Domain name and I'm switching to WordPress from the blog management system we use at MSDN. As a Mobility Architect at Microsoft, I will continue to give you my insights into the exciting world of Windows phones, wireless technologies, mobile hardware, the mobile web and Microsoft's mobile enterprise application platform (MEAP). Don't worry, you'll be getting my take on competing technologies as well. I enjoy seeing many of you both at Microsoft and at the events that I speak at all around the world. Now you have another place to hear from me. Come visit and subscribe to my RSS feed over at robtiffany.com. Happy Holidays everyone!

Best Regards,

Rob

What ever happened to RDA?

robtiffany — Wed, 23 Sep 2009 03:54:00 GMT

Who remembers using Remote Data Access to synchronize data between SQL Server and SQL Server Compact? I certainly do!

Before I dove head first into the world of Merge Replication, I always used RDA to get my customers up and running quickly. Mobilizing an organization’s workforce quickly and easily is what it’s all about so they can start reaping the benefits. In addition to a speedy time to market, there’s no faster or more scalable mobile sync technology on the market anywhere.

So why wouldn’t I always use RDA? Here’s a quick list:

You’re using Identity columns.
You want to replicate schema changes to the client.
You want change tracking on both the client and server to perform diffs of each of the tables during a sync instead of re-downloading the entire table.
You want to automatically resolve conflicts that arise when 2 people update the same data.
You want referential integrity constraints to be pushed down to the client database from SQL Server.
You don’t want to write code to perform synchronization or filter data.

If anything on the above list applied to you, you would shift to Merge Replication because it could manage ranges of Identity columns, push down schema changes, only sync data differences, resolve conflicts and push down a database’s referential integrity constraints. Merge requires almost no code to get started and tables and columns are filtered visually via a wizard.

So why might you choose to use RDA? Here’s another list:

Your Primary Keys use GUIDs instead of Identity columns.
Users don’t overwrite each other’s data so you don’t need conflict resolution. The rule of “Last in Wins” works for you.
While you want indexes to be pushed down, you don’t care if your local SSCE database has referential integrity constraints applied.
You want to wrap the changes you upload to SQL Server in a transaction so that all changes are applied or none of them are.
Change tracking on the client is good enough and re-downloading updated server tables doesn’t take too long.
You developers don’t mind writing some sync code.
Be able to execute SQL and Stored Procedures directly against SQL Server via IIS.

If your solution meets the criteria in the list above, you’re probably a good candidate for using RDA instead of Merge. Are there any other choices out there?

Back at MEDC 2007, we announced a new data replication technology for devices called Occasionally Connected Sync that would sit somewhere between RDA and Merge. OCS as it used to be called was renamed Sync Services for ADO.NET and then was eventually merged into the Sync Framework.

The Sync Framework is a developer-focused technology:

Supports conflict resolution.
Change tracking on the server as well as the client so that only data differences are exchanged.
Peer to Peer sync in the forthcoming v2 of Sync Framework.
Sync with databases other than SQL Server.
Best suited for SSCE running on a desktop or laptop.

The clearest differentiation that the Sync Framework has over Merge is its provider model which allows it to sync with other ADO.NET databases like Oracle or DB2. SQL Server supports built-in P2P Transactional replication and v2 of the Sync Framework will allow you to do this via WCF. If you development team doesn’t mind writing lots of sync code and needs to support scenarios like synchronizing with other databases from SSCE on the desktop, then the Sync Framework might be the way to go for you. I wouldn’t yet recommend the Sync Framework for device sync since its wire protocol is currently based on the DataSet which may cause out of memory errors on Windows phones with limited working sets.

So where does this leave RDA?

The reason I’m writing this blog post is because time and time again I run into customer sync scenarios that don’t always need the power of Merge or the extra flexibility of the Sync Framework. Most field service applications follow the same kind of pattern:

Lots of download-only lookup/reference tables that aren’t changed by the user.
Tables that are pushed down to the device that tell a user where to go and what to do.
Tables (sometimes empty) that are used to capture data from the user in the field that are upload-only.

These kinds of schemas don’t require conflict resolvers or server change tracking and are therefore well suited for RDA.

What’s the big benefit of using RDA if a sync scenario meets its criteria?

You won’t modify SQL Server’s schema with GUIDs and Triggers.
You won’t degrade the performance of SQL Server by having it track changes and maintain extra metadata.
You will have the fastest and most scalable sync solution with least amount of hardware.
Time to market is shorter.

The big takeaway here is that I want you to consider your sync solution carefully before choosing a technology. If your customer’s needs are met by RDA, then you should use it and reap the benefits of developing and deploying a simpler solution with fewer moving parts.

Remember Occam's Razor.

-Rob

Mobile Architecture Pocket Guide v1.1

robtiffany — Sat, 17 Jan 2009 21:01:00 GMT

Just wanted to let everyone know that version 1.1 of the Mobile Architecture Pocket Guide is now available on CodePlex at http://www.codeplex.com/AppArch/Release/ProjectReleases.aspx?ReleaseId=19798. This is the first patterns & practices update to this guide since 2002 so it's a welcome sight to to have it out there for all our Windows Mobile developers.

I've spent the last couple of months working with J.D. Meier, Rabi Satter, Rob Boucher and the rest of the P&P team to tune, tweak and update the new Mobile Architecture Pocket Guide to ensure that it's as accurate and relevant to today's Windows Mobile platform and runtimes as possible. The guide's chapters include:

Ch 01 > Mobile Application Architecture
Ch 02 > Architecture and Design Guidelines
Ch 03 > Presentation Layer Guidelines
Ch 04 > Business Layer Guidelines
Ch 05 > Data Access Layer Guidelines
Ch 06 > Service Layer Guidelines
Ch 07 > Communication Guidelines
Ch 08 > Deployment Patterns

Our goal is to empower our Windows Mobile developer community as much as possible, and while this guide may seem like it's targeted exclusively to developers, I ensured that the IT Pro side of the house is accommodated as well. Mobile infrastructure elements of this guide include System Center Mobile Device Manager (Deployment), SQL Server (Sync Services + Merge), IIS (Web Services + Sync + WCF), Exchange (WCF Store and Forward) and Active Directory (Auth).

Download it, take if for a spin, and give us your feedback so we can keep improving it.

- Rob

See you in Barcelona for Tech Ed EMEA Dev

robtiffany — Fri, 07 Nov 2008 19:14:00 GMT

Looking forward to seeing lots of familiar faces and meeting new ones starting December 10th at Tech Ed EMEA! While I ran the Windows Mobile track for Tech Ed North America last June in Orlando, this time around I'll just be delivering a couple of presentations and spending most of my time helping empower delegates to create incredible mobile applications. I'll be delivering the following breakout sessions:


	MBL301	What's New in the Windows Mobile Line of Business Solution Accelerator 2008	November 10 16:00 - 17:15	Room 121
This session walks through the new features that we have added to the Windows Mobile Line of Business Accelerator 2008; features such as adapting your application to any device or screen size with a single binary, sync services, store and forward, and advanced data access objects with Microsoft .NET CF 3.5.


	MBL310	Mobilize your Enterprise and Achieve Global Scalability with Windows Mobile and SQL Server Compact	November 11 15:15 - 16:30	Room 121
With the world's largest organizations rolling out tens of thousands of Windows Mobile devices to empower their respective workforces, the ability to create mobile line-of-business solutions that can support large user populations is critical. Based on his third book on Windows Mobile development, Rob Tiffany shows you how to take the Microsoft SQL Server data you use to run your organization and make it available to all your mobile employees. Utilizing the performance, scale-out, and filtering capabilities of Merge Replication Republishing, Rob shows you how to build an n-tier mobile synchronization architecture designed to scale to hundreds of thousands of devices. Take the guesswork out of mobilizing your enterprise by tapping into the experience of one of the world's foremost authorities on Windows Mobile infrastructure and development.

See you there!

- Rob

Chapter 1 of my new Book is Ready!

robtiffany — Fri, 24 Oct 2008 04:12:00 GMT

Mobile Data Synchronization with Microsoft SQL Server 2005 and SQL Server Compact > Second Edition

Achieving Global Scalability via Merge Replication Republishing

Download and review the PDF from my Windows Live SkyDrive @

http://cid-8b9c82da88af61fc.skydrive.live.com/self.aspx/Sync/Ch%201.pdf

The new book shows you how to scale out your Merge Replication Architecture with Republishing. It's chock full of new insight to show you how to get the most performance and scalability out of your system. It also shows you how to make replication Subscriptions available to the Internet via ISA Server 2006 or System Center Mobile Device Manager.

Check it out and let me know what you think.

Best Regards,

Rob

Listen to Rob's Windows Mobile Interview on .NET Rocks!

robtiffany — Thu, 09 Oct 2008 23:07:00 GMT

I was recently interviewed by Carl Franklin and Richard Campbell who run one of the Internet's most popular developer sites, .NET Rocks! You can catch the interview at http://www.dotnetrocks.com/default.aspx?showNum=384 where you can either listen to it live via the website, or download it to your favorite device to listen later.

I cover the current state of Windows Mobile + the entire ecosystem including OEMs, Mobile Operators, developers and who does what within Microsoft's Mobile Commications Business in Redmond and the Mobile Development Center in Hyderabad. I take Carl and Richard on a deep dive of our latest mobile development technologies and techniques with the .NET Compact Framework, SQL Server Compact, and WCF Store and Forward just to name a few. I also cover all the features of System Center Mobile Device Manager including OTA software distribution, Group Policies, Mobile VPN security and Domain join.

Download it and give it a listen

- Rob