Moses' Blog

Live in Australia, work at Readify

Fri, 20 Jan 2012 19:26:58 PST

Introduction

I moved to Australia recently (since Aug 2011) after I joined Readify team in Melbourne, VIC. I have to say since then it has been a great experience in such short time.

Readify is hiring national wide & overseas. For overseas candidates; Readify will sponsor you to come & work with them in Australia. Why don’t you read about our recruitment process?

About Readify

Readify was founded in 1999. Since this time they have established themselves as certified experts on the .NET Application Development Platform within Australia.

You can read more about Readify here.

Australia is a great multicultural country. Readify is tiny version of that. It’s a multicultural environment company. Over 30 nationalities working here at Readify. All gifted, talented software development geeks. Many of us are also community activists in different areas around Microsoft technologies.

So it’s a multicultural company of smart people from all over the world. It’s diversity in culture with equal opportunity to everyone.

Readify is hiring

Mohamed Meligy an Egyptian fellow working at Readify team in Sydney, NSW posted a cool blog post about this topic “Hey, Readify is hiring all across Australia, from all over the world!”. It’s a good to read post if you want to know few more about Readify. You’ll read about different iconic smart people working at Readify. An I guarantee that it’s just a very small sample. A blog post won’t be enough to cover all of them and their contribution to developer communities.

Readify is hiring national wide & overseas. For overseas candidates; Readify will sponsor you to come & work with them in Australia. Why don’t you read about our recruitment process?

Have a look at the available positions (Sr. Developers, Sr. Consultants)in different Australian states. Then go ahead and apply online or send your CV to careers@readify.net. And if you have any question contact our recruitment manager.

One thing I want to highlight, Senior developers are consultants at the end of the day. Read positions description of each available position to know the differences between both.

Why Readify

The main reason I decided to get out of the Middle East was the management and the way people think and work in my home region.

I had my expectations for Readify too. I used to have a friend who used to work with Readify. From what he told me I decided to apply.

Readify exceeded my expectations from different aspects. It’s very comfortable working environment. What I mean by environment is that they give you the choices and help you to get what you wish to work on. You just need to keep your working profile up to date.

They assist you in your Professional Development through their PD program. They will give you the time, you just need to start it. It’s your career PD at the end of the day.

They invest in you because they believe in your capabilities and skills. They support you and assist you to do things the right way in a standard way during your engagement with different clients.

Depending on your engagement. You could work on client site, or from home, of maybe in different state. So many options with different project types using different Microsoft technologies.

For example, my first engagement (~3 months) I was using MVC3, IoC, CSS3 & JavaScript. My current engagement (could reach ~6 months) I’m using WPF4, WCF4, MEF, EF4.1, IoC & many other things.

Which state I should work in?

I’ve worked in 2 States since I arrived. First engagement for 2.5 months was in Perth, WA –Western Australia-. And then moved back to my home state Melbourne, VIC –Victoria-.

Perth is a wonderful city. I guess they call it the Sun city. Its weather is awesome. I have to say being in Australia the weather is challenging. But living in Perth you are in what I called normal Middle Eastern weather, its not the gulf region weather and also not messy winter weather.

The government of WA in Perth is trying to make it’s people happy to attract population. Lot’s of free events, free transportation regions –transits- and many other things. It is a wonderful city I must say.

Readify team WA is really cool. I believe I met most of them in different gatherings and also during my engagement. Yes WA team loves to meet frequently. And when another Readifian member from different state is visiting, they have to celebrate this day somehow. I really enjoyed being with them.

My home city Melbourne, VIC. This is where I belong & I love it. Well it’s my home. I must love it.

Other available states are QLD, Queensland (city of Brisbane) & New South Wales, NSW (city of Sydney). I don’t know much about those 2 states as I never been there. But anyplace in Australia is a good place to live in.

Egyptian developers, you should try to apply

As I’m Egyptian. And I’ve worked with many good developers in Egypt. I believe we do have many talented developers that would meet Readify expectations. And you should know that expectations are high. Readify works by standards. And they strictly follow these standards to guarantee the delivery of high quality software development services.

You don’t have to worry. The recruitment process will decide if you’ll fit or not.All you need is to apply. Give it a shot and leave the rest to the recruitment team. You should know that the process itself is a good experience to have with Readify.

My experience, I applied back in 2008 and I failed at code review stage. And I reapplied in 2010 & passed. You can apply in 6 months –or as they advise you-. That was just me who took too long to reapply.

uCertify M70-668: Pro Microsoft SharePoint 2010, Administrator Product Review

Mon, 17 Oct 2011 06:23:22 PDT

Introduction

Before taking any exam, we usually start to prepare for that exam. Using official learning material like Microsoft learning products, reading blogs and articles or using exam preparation tool. And maybe all of that. The easiest way is to go through an exam preparation and simulation tool.

But that about a tool that gives you a preparation guide to help you learn, practice and track your results. This is pretty much what uCertify exam preparation products would give you.

And here I’m going to give you an overview and a review about uCertify M70-668: Pro Microsoft SharePoint 2010, Administrator

About uCertify

Founded in 1996, uCertify is a leading provider of exam preparation solutions for IT certifications from leading vendors such as Microsoft, CompTIA, Sun Java, Oracle, CIW, Adobe and Cisco. They are committed to help their clients to pass their certification exams by providing the highest quality preparation software. uCertify has devoted much of its resources in Computer Assisted Learning (CAL) research. Through continuous research and development, our products are designed and updated to cater to the needs of changing technology. uCertify PrepKits replicate the actual online exams, and help you experience the real exam environment. This gives you the confidence to pass your certification exams in the first attempt.

About M70-668 Pro Microsoft SharePoint 2010 Administrator

This preparation guide can be considered an all in one. Although you can use to learn about SharePoint 2010 but being familiar with SharePoint 2010 is must before start going through it.

The tool covers the exam pretty well. And uCertify Guarantee 100% Test Pass.

Study

The tool gives you study guide through organized learning subjects that covers exam objectives.

Inside each chapter there are several quizzes that cover different section in side the chapter. Which gives you the ability to test and practice your knowledge on the fly and as you move through the content.

About Study Notes & How tos

I find this pretty cool. There is around 88 study notes to learn about different subjects covering the exam objectives. On each study note you can jump to it’s related questions. And each time you jump to the related questions you are actually inside a test. It will be tracked and you can review your test results later.

How tos are a bit different. They are actually simple tiny walkthroughs to show you how to accomplish certain tasks. e.g. How to enable SharePoint alerts. This tool has around 13 How tos

Practice

You can start practice your skills immediately with 4 different types of tests.

Diagnostic test (15 questions)
Quick assessment to determine your initial level
2 predefined practice tests (58 questions each)
Learn mode enabled tests. Gives you ability to review the answer of each question with learning tips & explanation
Final test (40 questions)
Get into action with full simulation of the actual exam. Supposed to be closed book and no cheating allowed
Interactive quiz (102 question)
Validate your knowledge of the key concepts covering the exam objectives. This is one way test practice which means you have no option to go to previous question and each question has it’s own time limit which you can customize before starting the quiz as in the following figure.

In addition you can create your own custom tests. And in fact there are few auto generated custom tests that are created on the fly. For example when you jump from a study note to its related questions. There is a custom test created that has this subset of questions.

Tracking

You can track practice history. Each test or quiz to take is tracked. And you can get back and review your history. Retake a specific test, review wrong ones, delete your history etc..

Other cool features

There are pretty other cool features like tagging question, adding your own notes to each question and discussing questions or topics with others online.

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 6

Tue, 27 Sep 2011 05:55:12 PDT

About Part 6

6th part is about 12 min in length. Covers Entity SQL, LINQ to Entities and EF4 new feature of using database built in functions & user defined functions UDF. And how to use them with LINQ to Entities.

I just posted 6th Part of this screencast to my channel on your tube.Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

New Arabic Screencasts about SQL Server

Fri, 15 Jul 2011 19:27:00 PDT

Ahmed Mosa (my brother) a SQL Server & BI specialist produces a series of Arabic screencasts about different topics related to SQL Server. Find links below.

He’s also working on recording more screencasts so keep tuned through his RSS and his Youtube channel

Book Review: Programming Entity Framework, Second Edition

Sun, 02 Jan 2011 10:07:42 PST

About the book

Title: Programming Entity Framework 2^nd Edition
Publisher: O'Reilly Media
URL: http://oreilly.com/catalog/9780596807252
Book website: http://learnentityframework.com/
ISBN: 978-0-596-80726-9
Chapters: 27 + 3 Appendices | ~900 pages
Author: Julia Lerman
Author’s blog: http://thedatafarm.com/blog/
Overall rating: 9.70 out of 10
This is the second edition of the book totally revised for Entity Framework 4.0 on VS2010 1^st edition was released Jan 2009. this 2^nd new edition released August 2010.

Personal Opinion

I can’t do anything but strongly recommend this book. It is almost everything you might need about Entity Framework 4.0. Great walkthroughs and samples in C#. However there are few snippet in VB.Net that shows different syntax of doing things between C# & VB.Net.

What I liked about the book

The book is very well organized. Suitable for both experienced Entity Framework developers & newbies in Entity Framework. For experienced developers they can pick the chapters in any order they wish. And for newly comers, following the chapters sequence couldn't be much better.
Walkthroughs & samples are very well written.
I liked how Julie recommends the new APIs when applicable over the old ones that already exists since the first release of Entity Framework in .Net 3.5 SP1. I also liked how she propose her coding convention which I personally admire.
On each chapter, when some topic goes beyond the scope of the chapter, you'll find a reference to another chapter that should contains much more details. I personally think this is great to give better navigation guide around the book especially for eBook version.
I like the trap hints and tips & sidebars on every chapter. Very helpful information & tips.

What I didn’t like about the book

It is just too long. Almost reached ~1000 pages. However you don’t need to read it all. I did because I didn’t want to miss single tip that I might regret not reading it.

Another thing, in some chapters I didn’t like the practice being used like in Chapter 27 –storing customer related data in session-. The whole idea about me not liking this is just some developers will take it as common practice while it is not. However Julie was careful to hint most of times that these are not considered best practices and it is just for demonstration.

Book description –as stated in the book page–

Get a thorough introduction to ADO.NET Entity Framework 4 -- Microsoft's core framework for modeling and interacting with data in .NET applications. The second edition of this acclaimed guide provides a hands-on tour of the framework latest version in Visual Studio 2010 and .NET Framework 4. Not only will you learn how to use EF4 in a variety of applications, you'll also gain a deep understanding of its architecture and APIs.

Written by Julia Lerman, the leading independent authority on the framework, Programming Entity Framework covers it all -- from the Entity Data Model and Object Services to WCF Services, MVC Apps, and unit testing. This book highlights important changes for experienced developers familiar with the earlier version.

Understand the core concepts you need to make the best use of the EF4 in your applications
Learn to query your data, using either LINQ to Entities or Entity SQL
Create Windows Forms, WPF, ASP.NET Web Forms, and ASP.NET MVC applications
Build and consume WCF Services, WCF Data Services, and WCF RIA Services
Use Object Services to work directly with your entity objects
Create persistent ignorant entities, repositories, and write unit tests
Delve into model customization, relationship management, change tracking, data concurrency, and more
Get scores of reusable examples -- written in C# (with notes on Visual Basic syntax) -- that you can implement right away

Programming Entity Framework at glance

The book is divided into 2 parts consisting of 27 chapters plus 3 appendices making around ~900 pages. I recognize this book as 2 books in one. First part second part can be considered as the 2 books. First part ((ch01-ch12) ) as the author stated can be considered as introduction to Entity Framework. While second part (ch13-ch27) takes you much deeper into details of Entity Framework. So it can be considered as the advanced part of the book.

Chapter 01 - Introducing the ADO.NET Entity Framework

Rate: 10/10

As Julie stated, this chapter could be called, "It's time for Entity Framework" showing why it's important and why it's Microsoft recommended data access technology. Highlighting that Entity Framework is being used as part of some Microsoft products.

I really love how the chapter introduces almost everything about entity framework highlighting the chapters that will cover these topics in details. The Chapter is like scouting journey map that tells you what you are going to learn during this journey.

I think it is a must read chapter. It's the door for the book, where if you are already familiar with Entity Framework, you'll jump to the chapter(s) you wish to focus on. And if you are new to Entity Framework, the chapter will open you mind to what you are going to learn.

This chapter basically introduces you to critical pieces of Entity Framework. You'll learn about those things that give Entity Framework it's core value, understanding that Entity Framework is where you program against business models.

Julie shows in a simple clear example how database schema is represented with entities in Entity Framework EDM. With different database engines of your choice, you should only worry about your business object model. The chapter also introduces tools and APIs (at glance) that forms the core features of Entity Framework.

Chapter 02 - Exploring the Entity Data Model

Rate: 10/10

Highlights the benefit of using EDM and programming against conceptual model with detailed tutorial walkthrough on building your first EDM using Entity Framework with VS2010.

Start exploring your generated EDM under a microscope to learn more about EDM. Learn about different terms used descripting entities and their properties in EDM.

You’ll also learn about different windows in EDM Designer that will assist you modifying and gain control over the design time of your EDM.

You’ll explore XML parts (CSDL, SSDL & MSL) that forms the EDM. And if you are interested to diver deeper there is appendix that should assist you dig deeper into XML that forms EDM parts.

Chapter 03 - Querying Entity Data Models

Rate: 10/10

Learn the foundations of querying data using Entity Framework. No deep dive in this chapter, just warm up with query options you have. Have a look at generated code by VS2010 EF Designer of your EDM. Explore the classes and understand them clearly

Demonstrate how to querying data using Entity Framework applying same query with different styles & flavors of queries supported by Entity Framework through clean and descriptive walkthroughs.

The chapter will help you to gain a high level understanding of all of the query options and their basic uses.

I like that the chapter introduces LINQPad to readers. Because it gives them the ability to test queries without the need of building sample console application to test those queries when the EDM is read. Same thing for EfProf to analyze and profile the performance of your queries made with Entity Framework.

Chapter 04 - Exploring LINQ to Entities in Greater Depth

Rate: 9.75/10

Learn about critical features of querying your model using LINQ to Entities focusing on the most typically needed query features. You are going to dive deep so you better be prepared with some LINQ skills before you start reading this chapter.

You’ll learn:

How to do filtering, projection, sorting, joins, aggregation, grouping and query across relationships using LINQ to Entities. Learning about querying isn't going to stop by this chapter, there are a lot more examples and samples in subsequent chapters.
About projection, eager loading, differed loading, lazy loading and navigating using navigation properties. You'll also learn about anonymous types and how you can return anonymous types from your queries and how this can help you be flexible.
How to build nested queries to serve different query scenarios.
About different loading options of entity's related data such deferred loading, lazy loading and eager loading. Discover the pros and cons of each approach.

I really liked how Julie -when applicable- differentiate between C# & VB.Net syntax when using LINQ.

Chapter 05 - Exploring Entity SQL in Greater Depth

Rate: 9.5/10

Another deep dive about querying with Entity Framework, this time in Entity SQL.

You’ll learn:

About the differences between LINQ to Entity and Entity SQL and explore different scenarios where Entity SQL could a better choice.
About critical features of Entity SQL and what makes it great querying language for Entity Framework. You'll also learn about its limitations.
How to do filtering, projection, sorting, joins, aggregation, grouping and query across relationships.

The take on this chapter is that I wished that for certain queries Julie could provide the output results of queries. Especially those queries that looks similar to each others except for a slight difference that change the shape of the returned data.

Chapter 06 - Modifying Entities and Saving Changes

Rate: 10/10

Take a high-level look at the way in which the Entity Framework is able to track these changes and get the necessary data back to the database. This is like the ABC of Insert, Update, Delete operations using EF

You’ll learn:

How to perform updates, inserts, and deletions with Entity Framework object services. And go under the hood to see what happens in the database in response.
How Entity Framework manage to track changes of your entities behind the scene.

Chapter 07 - Using Stored Procedures with the EDM

Rate: 10/10

In this chapter you’ll learn:

How to override the Entity Framework’s command generation feature for a particular entities and direct it to use your custom stored procedures when persisting changes to database.
How to build and map stored procedures that returns data to existing entities in your EDM as well as stored procedures that return scalar values. You'll also learn how to map a result from a stored procedure to complex type.
About different mapping designer windows and model browser window in EF Designer inside VS2010
About combining entities that map to database views with stored procedures to provide fully functional entities that completely avoid direct table access.

Chapter 08 - Implementing a More Real-World Model

Rate: 10/10

On this chapter you'll start to meet the real world with Entity Framework creating a more realistic EDM based on a database of the kind you’re more likely to encounter in your work. However the model is still smaller than a typical enterprise model saving you distraction and confusion for faster and better understanding of real world EF applications.

You’ll learn:

How to build you model in separate assembly so that you can reuse it. And in fact it is going to be reused throughout the rest of the book.
How you can manage your entities by renaming them or their properties. And explore what kind of conflicts you might face. Also it shows you how the separation between the conceptual model and your database structure is of a great benefit.

The chapter is alike a walkthrough on all the previous chapters to build real-world model.

Chapter 09 - Data Binding with Windows Forms and WPF Applications

Rate: 10/10

Explore basic data-binding scenarios in Windows Forms and Windows Presentation Foundation (WPF).

See how the Entity Framework objects work with Visual Studio’s data-binding features. The chapter does not presume that you are familiar with Windows Forms or with WPF data-binding techniques in the VS2010 IDE and so it moves step-by-step walkthrough to be sure that the UI tasks don’t trip you up.

This chapter contains long walkthroughs on working with Entity Framework on Windows Forms and WPF,

You’ll learn about Data Source Controls in Windows Forms & the difference between object data source & Data Source that interacts directly with the database. The WPF part of the chapter shows how to use WPF new Data Binding capabilities provided through VS2010 with Entity Framework.

Chapter 10 - Working with Object Services

Rate: 10/10

In this chapter you’ll gain better understanding of the Object Services API, what it’s responsible for, what it does under the covers, and some of the ways that you can take advantage of it. You are going to have a closer look at the ObjectContext, the most important Object Services class.

You’ll learn:

Learn how you can take charge of your entity objects using Object Services APIs.
How queries are processed and turned into objects, how these objects are managed during their life cycle and how Object Services is responsible for the way entities are related to each other.
How the ObjectQuery and the new ObjectSet work and how they relate to LINQ to Entities queries under the covers.
Beyond the basics and understand of how Object Services manages an entity’s state.

Chapter 11 - Customizing Entities

Rate: 10/10

In this chapter you’ll learn

How Entity Framework provides a number of ways to not only add your own logic, but also use your own classes and plug them into an ObjectContext.
How to use partial classes to add new logic to entities or override their existing logic. Understand the criteria and of creating partial classes.
How to change the rules for code generation and in doing so create classes from the model that are more to your liking.

Chapter 12 - Data Binding with RAD ASP.NET Applications

Rate: 10/10

this chapter is about how to build RAD ASP.NET web applications using entities that make use of the EntityDataSource control. You’ll take tour of some of the more interesting features of the EntityData Source control You’ll see what EntityDataSource do behind the scene to maintain your changes to your entities across page PostBacks.

You’ll also build a quick ASP.NET Dynamic Data website so that you can see how Dynamic Data simplifies some of the manual tasks you have to perform when using the EntityDataSource directly.

The chapter won’t delve too deeply into this area, as you can learn much more about these in many ASP.NET resources.

Chapter 13 - Creating and Using POCO Entities

Rate: 10/10

This chapter will introduce you to what is persistence ignorance and what are Plain Old CLR Objects also known as POCOs.

You’ll learn:

The basics of how to manually create and work with POCOs in Entity Framework to manage these classes so that it can perform its job of executing queries, returning objects, persisting changes to the database, and so forth.
How to generate POCOs using T4 templates.

Chapter 14 - Customizing Entity Data Models Using the EDM Designer

Rate: 10/10

You will spend much of your time in this chapter working directly with the XML. You’ll learn:

About some of the many ways in which you can customize an EDM, the benefits of these customizations, and when you would want to take advantage of them. All this through a step by step walkthroughs that will give you detailed information on how to apply mapping customization.
How to build Table per Type inheritance with EF. And how to perform queries against this model as well as insert, update & delete. You'll also understand what's happing behind the scene on database level.
How to map an entity to more than one table and to split single table to more than one entity.
How to create complex types and use them in your model.
How to build queries using the new mappings and interact with the objects that are based on the various entities

Chapter 15 - Defining EDM Mappings That Are Not Supported by the Designer

Rate: 10/10

In this chapter you’ll learn:

How to modify the XML manually to build model-defined functions, table per concrete type inheritance, and QueryView.
How to write model defined functions using Entity SQL and use them in your query model using LINQ to Entities.
How to build and use QueryView to Create Read-Only Entities and Other Specialized Mappings. You'll understand constrains to build QueryViews.

Chapter 16 - Gaining Additional Stored Procedure and View Support in the Raw XML

Rate: 10/10

Cover ways to implement stored procedures beyond the function mapping you already performed in the Designer. These additional implementations will create functions that you can call directly in your code. You’ll learn how to create native functions and views directly in your model.

Chapter 17 - Using EntityObjects in WCF Services

Rate: 10/10

Write a WCF service that makes use of EntityObject-based entities. If you have never built a WCF service before, have no fear. The walkthroughs will provide you with step-by-step details

You’ll learn about some of the complications that arise (and their solutions) while you work across the tiers of a distributed application. And take a quick look at WCF Data Services and WCF RIA Services in order to get an understanding of how they relate to the Entity Framework.

Chapter 18 - Using POCOs and Self-Tracking Entities in WCF Services

Rate: 10/10

Get introduced to Entity Framework new feature of Self-Tracking Entities. You’ll learn:

How to create WCF-Friendly POCO classes.
How to separate your models in separate class library project and reuse it in your WCF Services through a complete and clear walkthroughs.
How to build Entities using T4 template in VS2010 and build a WCF service that uses Self-Tracking Entities
About the impact of using POCO entities in WCF Data Services and WCF RIA Services instead of EntityObjects.

Chapter 19 - Working with Relationships and Associations

Rate: 10/10

In this chapter you’ll dig much deeper into how relations and associations in Entity Framework are built and managed.

You’ll learn:

How relationships and associations fit into the EDM and how they work both inside and outside the ObjectContext.
How to manipulate relationships between entities, adding or removing relationships between objects in the way that the Entity Framework expects; you will be able to solve problems that arise because of relationships; you will even enhance your ability to build more meaningful Entity Data Models.

The chapter is divided into two parts.

The first part is devoted to teaching you how relationships and associations work in the Entity Framework, from the EDM to the EntityObjects.
The second part will teach you how to perform a number of critical tasks relating to entity graphs as you work with sets of related entities.

Chapter 20 - Real World Apps: Connections, Transactions, Performance, and More

Rate: 9.5/10

In this chapter You’ll learn

More about working with entity connections and the database connections that they create for you, and how to explicitly open and control those connections, even when interleaving read and write operations to the database.
How transactions work by default, as well as how to replace the default database transactions that Entity Framework uses with .NET’s TransactionScope.
About different ways you can improve performance in Entity Framework, as well as the results of some performance comparisons made by the author.

You’ll also take a look at how to use Entity Framework in a few multithreading scenarios.

Chapter 21 - Manipulating Entities with ObjectStateManager and MetadataWorkspace

Rate: 9/10

Understand why ObjectStateManager & MetadataWorkspace classes are important APIs in Entity Framework. You’ll also learn:

How to use ObjectStateManager and MetadataWorkspace in your own applications to control and manipulate entity objects.
How to interact with entities and entity state through the ObjectStateManager
About interacting with the raw metadata using the MetadataWorkspace.

You'll build more samples that will give you great hands-on experience working with ObjectStateManager and MetadataWorkspace.The chapter also contains many code samples that you can use in your applications.

Chapter 22 - Handling Exceptions

Rate: 10/10

This chapter is short one and it is all about exceptions that are unique to the Entity Framework and how to handle them. Some exceptions are Entity Framework-specific exceptions, and others are .NET exceptions caused by faulty operations when using the Entity Framework.

The chapter tries to cover every possible scenario that might cause an exception when using Entity Framework and points your to the type of exceptions being thrown.

Chapter 23 - Planning for Concurrency Problems

Rate: 10/10

Learn about concurrency problem and its different types exploring different scenarios where concurrency problems can happen.

Learn how to set up your model so that the Entity Framework will alert you to conflicts when persisting data to the database, and then you’ll learn how to capture and handle OptimisticConcurrencyException

Explore different options to achieve concurrency checking when using Entity Framework.

Chapter 24 - Building Persistent Ignorant, Testable Applications

Rate: 8/10

This chapter is about bringing testability to applications that use Entity Framework. You’ll receive an introduction to testing and other agile coding practices while learning more about the Entity Framework and how to put these practices in action with Entity Framework. However this is a very narrow slice of agile programming & practices.

Chapter 25 - Domain-Centric Modeling

Rate: 9/10

Learn how to use the new model-first feature along with interacting with the design tools through a detailed walkthrough.

Also learn about Code First approach which is currently in CTP and the book actually discuss an old CTP. Current one is CTP5 and it is way different than the one mentioned in this chapter. But it will give you an idea of what is this about.

Get a short introduction to another future technology, SQL Server Modeling and its modeling language, currently code-named “M”.

Chapter 26 - Using Entities in Layered Client-Side Applications

Rate: 9.5/10

Explore ways in which you can disentangle the UI of a layered client application from its business and data access logic while retaining certain key benefits of the Entity Framework.

You’ll learn:

How to keep the data persistence code out of the user interface.
To focus on building application logic based on your domain needs, not based on the needs of a particular user interface through a detailed walkthroughs.

The chapter will help you gain a clear understanding of which code does and does not belong in the UI, most of this chapter will demonstrate restructuring the WPF application from Chapter 9. A side benefit is that you will get to leverage the UI that you’ve already created rather than building a new one.

Chapter 27 - Building Layered Web Applications

Rate: 8/10

Look at some better ways to use entities in better architected web applications.

You’ll build 2 different kind of ASP.Net web application where in the first you'll be using ASP.NET Web Forms application where you can take advantage of ASP.NET’s Session and ViewState features to retain object data across post backs. In the second you will use classes in a simple ASP.NET Model-View-Controller (MVC) application.

You’ll see how to separate the logic out using similar methods as you are supposed to learn in chapter 26. You’ll also learn a few tricks that are specific to entities in MVC applications

Appendices

There are 3 appendices. Appendix A about Entity Framework related assemblies & namespaces inside .Net 4.0. Appendix B is about Data binding with complex types. And finally appendix C gives additional details about EDM schema and Metadata.

Conclusion

This is almost everything about Entity Framework book. It’s long one, but that returns to the attempt to cover everything. And I guess the book succeeded. The book written carefully and fully revised for EF 4.0. I really appreciate the effort spent on the book to deliver this quality of well written walkthroughs & explanation.

I hope you find this review useful.

KiGG 3.0 Released

Wed, 13 Oct 2010 16:17:41 PDT

Yesterday we released KiGG 3.0 and baselined the source code for version 3. No major changes in this release. We upgraded to ASP.Net MVC 2.0 on .Net 3.5 SP1 & VS2008.

This release is going to be the last release on .Net 3.5 SP1 and VS2008. We plan to upgrade to .Net 4.0 and migrate the solution to VS2010 and start use Entity Framework 4.0 and maybe abandon LINQ to SQL support.

Visit http://kigg.codeplex.com for more information.

Here set of requirements for your development workstation if you are planning to rebuild the source code or customizing it.

Development Workstation System Requirements

Visual Studio.Net 2008 any edition with SP1 (Express Editions should work)
.Net Framework 3.5 SP1
ASP.NET MVC 2.0 RTM
Included reference libraries (xUnit, Moq, DotNetOpenAuth, Enterprise Library etc...) -available with source code download-
Database (Only one option is required)
- SQL Server 2005 or later any Edition with Full-Text Search Services (Full-Text search is required for search)
- MySQL 5.x
IIS 6.0 or IIS 7.0 (didn't test it on Windows XP IIS 5.5)

Book Review: Microsoft Entity Framework in Action

Mon, 11 Oct 2010 16:15:49 PDT

About the book

Title: Microsoft Entity Framework in Action
Publisher: Manning Publications
Url: http://www.manning.com/mostarda/
ISBN: 9781935182184
Chapters: 19 + 2 Appendices | ~500 pages
Authors: Stefano Mostarda, Marco De Sanctis, Daniele Bochicchio
Overall rating: 9.24 out of 10

This book was in Manning Early Access Program (MEAP) while writing this review. I reviewed a draft released on 12^th August 2010. This is a detailed review where I rate each chapter and describe it’s contents. The overall rating mentioned above is the average of all chapters’ ratings.

Personal Opinion

I highly recommend this book. No further knowledge about Entity Framework is required. So you don’t have to know anything about EF1 in order to read and gain benefit of this book. Great effort spent on this book by the authors and the publisher. You’ll get a great value with reasonable amount of money compared to the information provided in this book.

Book description –as stated in the book page–

Microsoft Entity Framework in Action introduces the Entity Framework to developers working in .NET who already have some knowledge of ADO.NET. The book begins with a review of the core ideas behind the ORM model and shows how Entity Framework offers a smooth transition from a traditional ADO.NET approach. By presenting numerous small examples and a couple larger case studies, the book unfolds the Entity Framework story in clear, easy-to-follow detail. The infrastructure and inner workings will be highlighted only when there's the need to understand a particular feature.

Microsoft Entity Framework in Action at glance

The Book is divided into 4 parts consisting of 19 chapters plus 2 appendices making around ~500 pages in the draft I reviewed. The book is very well organized. Its chapters follow good sequence where each chapter and each section hands you to the next one smoothly, making the flow of knowledge and ideas well organized in your mind.

Chapter 01 - Data Access reloaded: Entity Framework (free for download, visit the book page)

Rate: 10/10

This chapter is very important if you are new to O/RM world.

The chapter shows how relational database engines became more powerful in terms of features available to developers. And that relational databases are optimal to store data while objects are best way to represent them in applications as OOP allows a better coding style which ease the development.

Discussing classic ADO.Net data access way using DataReader and DataSet and challenges of being bound to the database structure. And the role of ORM in general in resolving Object/Relational mismatch problems and that it places itself between the application code and the database taking care of object persistence to the underplaying data store.

Showing the differences between the 2 worlds (relational databases Vs. objects) and how objects are used to represents data stored in database. And how Entity Framework plays its role as an ORM aiding developers to solve the mismatch between the paradigms and offering a convenient way of accessing data.

The chapter introduces Entity Framework as a free ORM choice part of .Net 4.0. Giving quickly overview on its architecture and design elements describing the role of each of those elements.

By the end of this chapter, you will have a strong knowledge of what an ORM is, what is it used for and why you should always think about it when creating an application that works with a database.

Chapter 02 - Getting started with Entity Framework

Rate: 10/10

This chapter starts clearly describing the sample application requirements being used across the book. Then moving through different options available to design the application using Entity Framework exploring different inheritance models supported by entity framework.

A detailed walkthrough on how to build your entity model using Entity Framework using VS2010 describing and explaining different aspects clearly focusing on Entity Framework capabilities as powerful ORM. Showing 2 different approaches to build applications using Entity framework using Database First and Model First.

Many Entity Framework basic stuff introduced here including entities and entity sets, complex types, inheritance models and how to work with Entity Framework designer through a detailed walkthrough tutorial. The chapter also introduces the basics of CRUD operations using Entity Framework.

Chapter 03 - Querying the model: the basics

Rate: 9.5/10

This chapter is about the basics of the most basic thing of Entity Framework: querying. You'll learn about different ways of querying with Entity Framework. In particular, you will learn how the Object Services layer enables you to query the database and which other components collaborate with it. It also shows how change tracking is managed through object services.

What's more, you will understand how to discover the SQL generated by Entity Framework so that you can decide whether use it or handcraft a custom SQL command. By the end of this chapter, you will understand what happens under the covers and the theory behind querying.

Chapter 04 - Querying with LINQ to Entities

Rate: 9.5/10

This chapter is about how to do queries using LINQ to Entities showing how to do filtering, projection, sorting and grouping. It also explores how to execute normal T-SQL queries.

The chapter describes new LINQ to Entities features supported in EF4 and weren't in EF1 such as using of Contains method.

The chapter explains clearly how to do filtering with single associations and collection associations. It also walkthrough how to do paging on entities using LINQ to Entities.

The chapter is like a journey on LINQ to Entities. Exploring different kind of LINQ extensions supported in LINQ to Entities covering set & aggregation methods.

You'll also learn about different loading strategies (Eager loading, lazy loading and manual deferred loading)

Chapter 05 - Domain Model Mapping

Rating: 10/10

The chapter started with a very nice quote "a strong knowledge of the Entity Data Model and model classes code is fundamental to really master Entity Frame". And this is what this chapter is about, it strength your knowledge about Domain Modeling & EDM with Entity Framework. This chapter covers mapping of tables or view to entities. Showing almost everything about EDM and manual mapping describing XML elements used by EDM.

Walking through how to build EDM files (CSDL, SSDL & MSL) manually. To give you better knowledge about EDM and XML elements form it.

Finally the chapter highlights that you can do customization in EDM. This could be useful to add validation to your model.

Chapter 06 - Understanding entity lifecycle

Rating: 10/10

This chapter is about entity lifecycle and change tracking of entities. And how entities are transformed from one state to another.

You’ll lean about how states can be changed for an entity showing that entity state is managed by its context and can be controlled by the developer. There is a good figure on this chapter showing the states of an entity and what context methods make it change.

The chapter talks about the internals of entity change tracking which actually gives you a strong knowledge about how Entity Framework manage this. This is a very big plus for the book and this chapter.

Chapter 07 - Persisting objects into the database

Rating: 9.5/10

Explore how to persist modification to the database (insert, update & delete) in both connected and disconnected scenarios. So you’ll learn more about the 2 different scenarios.

Lean how to do persistence of single object and complex object graph.

The chapter at the end shows how to deal with exceptions highlighting UpdateException instance thrown when an exception occur when persisting changes using EF. Also it highlights how to execute custom commands using EF.

Chapter 08 - Handling concurrency and Transactions

Rating: 9.5/10

Learn about concurrency problem and how it can be managed using Entity Framework. Walking through different solutions for concurrency problem, pessimistic approach & optimistic approach. Showing pros and cons of each approach.

The chapter shows that EF only support optimistic concurrency. And how it's applied on entities with relations and inheritance. The chapter introduces you to TransactionScope class. Also explains the transactional ObjectContext.

Chapter 09 - An alternative way of Querying: Entity SQL

Rating: 9.5/10

It's all about Entity SQL and why it's important comparing it with it's alternative LINQ to Entities. Walking-through Entity SQL History provide you with a solid knowledge about the origin of this language.

The chapter is going through Entity SQL shows the differences between Entity SQL language and the known T-SQL. Exploring different options available in Entity Framework to execute Entity SQL query.

Learn how to do filtering, projection, sorting and grouping with Entity SQL as you did with LINQ to Entities. You'll also learn about query builder methods in EF

The chapter unleash the power of Entity SQL showing when it can be much more powerful than LINQ to Entities

Chapter 10 - Working with stored procedures

Rating: 10/10

This chapter shows how to interact with stored procedures using Entity Framework to perform data retrieval and persistence. Walking through importing stored procedures into your EDM using EF Designer in VS2010 as well as manually showing you how to do mappings manually in EDM.

Chapter 11 - Working with functions and views

Rating: 9.5/10

Learn how to build model views in your EDM using Defined Queries; a hidden gem in Entity Framework.

Learn about Database functions and UDF -user defined functions-, how can you import them in your model and use them in your queries.

Learn about Model defined functions, what are they, how to create them and use them in your queries, both Entity SQL and LINQ to Entities queries.

Learn about tricks to over come some limitation shown in chapter 10 about mapping data returned from stored procedures to complex properties in your entity.

Chapter 12 - Exploring EDM metadata

Rating: 9/10

Learn about how to access your model EDM metadata using APIs why you might need to do such thing?

Learn different ways to access EDM metadata, moving step by step to get your MetadataWorkspace instance ready to work with.

Learn how to access different EDM schemas (CSDL, SSDL) as well as your entity classes using MetadataWorkspace.

Put what you've learnt all together to build and EDM Metadata Explorer.

Chapter 13 - Customizing code and designer

Rating: 8.5/10

Learn about VS Code generation templates built with T4. The chapter will teach you the basic of T4 code.

Understand the code generation template provided by Entity Framework team that supports POCO to be able to modify it.

Learn about VS2010 extension Entity Designer Database Generation Power Pack tool and how it can used to do assist you in Model First scenario. Leaning behind the scene of how the generation process of the DDL is performed through workflow foundation activities and T4 templates.

Chapter 14 - Designing the application around Entity Framework

Rating: 8/10

Learn how Entity Framework can be used to build application using Domain Driven Design and the design artifacts of DDD and where can Entity Framework fits on each layer.

Chapter 15 - Entity Framework and ASP.NET

Rating: 8.5/10

The chapter requires knowledge of building web applications using ASP.Net. And be familiar with ASP.Net Data Controls and Data Source Controls

Chapter 16 - Entity Framework and N-Tier Development

Rating: 8.5/10

Learn about N-Tier architecture and it's challenges and how to use Entity Framework with WCF services to build services using entities.

Learn different approaches to build service-oriented application using Entity Framework exploring pros and cons of each approach

Learn about Self-Tracking Entities, the Entity Framework proposed solution for N-Tier architecture and its pros and cons.

Chapter 17 - Entity Framework and Windows applications

Rating: 8/10

Learn how to adapt your entity classes to participate in data binding in desktop applications and what pattern to follow to take the best out of windows forms/WPF applications .

Learn about how to put code generation learnt in chapter 13 in action to implement data binding aware entities.

Walkthrough on how to build a windows forms application that uses Entity Framework with data binding facilities

Walkthrough on how to build a WPF application that uses Entity Framework with data binding facilities

Chapter 18 - Testing ADO.NET Entity Framework

Rating: 8.5/10

This chapter introduces the concept of Unit Testing while teaching you the basics of writing unit tests using MSTest in VS2101.

Learn about how to isolate your code under test from external dependencies in your unit tests

Learn about Mocking frameworks and how you can use one to fake dependencies used in your code under test.

Learn about integration testing with direct interaction with database to validate your Entity Framework based repository persist and retrieve data correctly.

Chapter 19 - Keeping an eye on performance

Rating: 9.5/10

A study on the performance of Entity Framework comparing it with classic ADO.Net way of accessing data. You are going to build an application to evaluate and compare performance of both Entity Framework and classic ADO.Net

Learn about different ways to enhance the performance of Entity Framework based data access.

Learn about how boost the performance of your LINQ to Entities Queries using Compiled Queries.

Learn about how enhance the performance of your Entity SQL using plan caching.

Appendices

There are 2 appendices in this book, Appendix A is about the basics of LINQ. You should read this Appendix if you are not familiar with LINQ and before starting chapter 03.

In Appendix B is about Tips and Tricks when working with Entity Framework. You should read after you finalize the book if this is your first time to learn about Entity Framework. Don’t miss it!

Conclusion

I highly recommend this book. It’s well written and organized. It does it’s goal by delivering high quality education materials on Entity Framework.

I hope you enjoyed this review.

Basic Introduction to Algorithms session at Alazhar University

Wed, 29 Sep 2010 15:27:21 PDT

I had a chance this week to do a simple basic presentation about algorithms to undergraduate students of Computer Engineering in Alazhar University in Cairo.

I enjoyed the time of the session. Both both an girls were amazing an interactive. I hope that I delivered this introduction about Algorithms properly to them.

I prepared this presentation in short time and actually made it to fit 50 min presentation time. As this was an introductory topic, my main source was wikipedia.

I had another goal to deliver in this presentation along with the main topic which is Algorithms. The goal was to direct the attention of students of the online available material about different subjects that touches their studies including Algorithms. I used one video available on YouTube that explains Bubble Sort Algorithm directly in my presentation.

You can download the presentation, view it directly from skydrive office web apps, or explore it directly from this post

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 5

Sat, 25 Sep 2010 08:12:19 PDT

About Part 5

Fifth part is about 9:45 min in length. Part 5. Covers EDM -Entity Data Model- showing its elements (SSDL, CSDL & MSL). Also this screencast shows how to query your conceptual model using LINQ to Entities.

I just posted 5th Part of this screencast to my channel on your tube. Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

Part 6 will be up soon. So keep tuned.

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 4

Sat, 07 Aug 2010 14:42:47 PDT

About Part 4

Fourth part is about 10 min in length. Covers how to implement table per hierarchy inheritance model (TPH) with Entity Framework 4.0

I just posted 4th Part of this screencast to my channel on your tube.Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 3

Sun, 11 Jul 2010 07:39:18 PDT

About Part 3

Third part is about 8:20 min in length. Covers how to use stored procedures with EF4 to do CRUD operations on the database. The demo shows how to do mapping to existing stored procedures. The Demo also shows how to use IntilleTrace to view executed statements made by EF object services.

I just posted 3rd Part of this screencast to my channel on your tube.Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

Part 4 will be up soon. So keep tuned

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 2

Fri, 18 Jun 2010 16:41:16 PDT

About Part 2

Second part is about 6:30 min in length. Covers Object Services and how to do CRUD operations using EF 4.0 object services. The demo explores EF change tracking capabilities. The demo also shows how to map return result of a stored procedure to existing entity in your EDM.

I just posted 2nd Part of this screencast to my channel on your tube. Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

Part 3 will be up soon. So keep tuned

Getting Started with Entity Framework 4.0 Screencast Recorded session from Cairo Code Camp - Part 1

Tue, 15 Jun 2010 13:41:48 PDT

Introduction

I finally decided not to wait till I finish the whole recording which it seems is going to take some good time. And so I started to split this recording session/screencast into multiple parts and post them.

About Part 1

First part is about 10 min in length. And is an introduction to Entity Framework 4.0 with brief about its short history. This part also include a demo about new vs2010 designer enhancements for EF4. Also the screencast shows how to do a refactor to complex type using EDM designer.

I just posted 1st Part of this screencast to my channel on your tube. Source code and presentation can be found here.

You can watch the HD version on your tube here. Also subscribe to my youtube channel for more upcoming screencasts. Download HD video.

Part 2 published. But keep tuned for upcoming parts.

Using LinqPad to Query OData Services – Screencast

Sun, 30 May 2010 00:00:00 PDT

Last week I introduced a new screencast on another OData Developer tool. It was about how to use LinqPad to query OData service with C#, LINQ & WCF Data Services Client APIs.

The screencast shows how to use LinqPad to connect to and query OData Services using LINQ and WCF Data Services Client APIs. Showing how LinqPad can be useful as a developer tool to test queries against any OData Service.

I case you missed it, you can watch it on ODataPrimer website. You can also download an HD video (~48Mbs). The package contains 2 videos. One of them is the one hosted and it’s a 10 min video. And the other is ~14 min. I had to trim it to fit into youtube. The 14 min video contains additional stuff in case you are interested.

You can also subscribe to ODataPrimer channel on yourtube for future updates and videos.

Hope you’ll enjoy it.

Open Data Protocol Visualizer Extension for VS2010 – Screencast

Mon, 03 May 2010 14:44:13 PDT

Last week I introduced a screencast talking about OData Visualizer Extension for VS2010 on http://odataprimer.com community.

It’s a How-To video on how to download, install and start working with OData Visualizer Extension for Visual Studio.Net 2010. OData Visualizer is an extension for VS2010 made by Microsoft Data Modeling team

I case you missed it, you can watch it on ODataPrimer website. You can also download an HD video (~35Mbs).

You can also subscribe to ODataPrimer channel on yourtube for future updates and videos.

Hope you’ll enjoy it.

Code Camp Reloaded at Faculty of Engineering ASU

Sat, 01 May 2010 10:35:24 PDT

Last month, Friday 23rd April, I had a chance to present at Code Camp Reloaded event hold at Faculty of Engineering Ain Shams University in Cairo.

My presentation was about Exploring Design Patterns. I gave a general introduction about what’s design patterns and why they exist.

In this session I talked about different Design Patterns categories and explored 2 interesting design patterns:

Decorator as example of structural patterns
Strategy as example of behavioral patterns.

I also demonstrated the 2 patterns and showed examples from within .Net framework itself where these 2 patters are applied and used.

I uploaded code samples and presentation to my skydrive

Download Exploring Design Patterns

Note: I uploaded all my sessions to skydrive, you can explore them here

Need Unit Testing Academy then join TypeMock Academy

Wed, 21 Apr 2010 19:08:32 PDT

TypeMock is holding its first TypeMock Academy on 27th April 2010 on Oslo, Norway. So are you interested in unit testing?! If you are, and you are software developer or consultant join them on this very first academy.

You can expect to see the following TypeMock experts while being there:

Eli Lopian
Roy Osherove http://weblogs.asp.net/rosherove/
Vagif Abilov
Gil Zilberfield
And more…

Along with very special appearance and very special guest Uncle Bob Martin

You can find more details on the Typemock site.

During the Academy Typemock will also release their new Test Lint VS 2010 RTM. You can try out the beta of Test Lint for free now: http://site.typemock.com/test-lint/

Facebook RSVP.

Introducing Shrinkr The URL Shrinking Service built with ASP.NET MVC 2

Tue, 20 Apr 2010 09:25:48 PDT

Few months ago, on September 2009 my friend Rashid started to blog about this open source project “Shrinkr”. And I got a chance to assist him on this.

In the last few weeks we were working on preparing this first stable release. And now we got it and it’s live on http://rdir.in.

Yesterday Rashid announced the first release which you can download from here.

In this post I’m going to show few screenshots of the live Shrinkr. And highlights few technologies used on it.

Shrinkr developed using the following tools:

.Net Framework 4.0 (Its now ready for RTM)
ASP.NET MVC 2
jQuery 1.4.2 (Current release at the time of releasing Shrinkr v1)
Entity Framework 4 using Code First. So there is no EDMX or Xml for CSDL, SSDL or MSL
AspNetMvcExtensibility. An open source project developed by Rashid. Very helpful tool that contains ready to use stuff to address common ASP.NET MVC usages with best practices.
Telerik Extensions for ASP.NET MVC (Freely to use in open source project)
DotNetOpenAuth 3.4 for OpenID support.
Elmah for error handling & logging.
MoQ 4 as mocking framework in unit tests
xUnit 1.5 as unit testing framework.

For list of features available on this first release kindly return Rashid’s announcement post.

I prefer to mention what is not available at this release:

Non OpenID Login mechanism. And so far we think there is no demand for another login mechanism.
No Profile edit. You cannot edit your profile at this first release. However you can generate your API Access key to access the service programmatically using REST API. Of course if you are allowed to.
Audit of who did what! Like audit about that this a specific user is locked by some admin. Or that a URL is marked as spam by spam detector or manually by an admin.
No Email notification in case of spam detection. Currently only twitter direct messaging supported.

Rashid mentioned few features that we plan to support in next minor releases as well as other features for upcoming major releases.

I hope you’ll enjoy it. So start downloading it and have a look at the code, and check it running live on http://rdir.in.

uCertify's Spring Sale

Thu, 15 Apr 2010 13:11:42 PDT

I thought to bring your attention about uCertify’s Spring Sale. Currently, uCertify is celebrating and welcoming spring with a Spring Sale. uCertify is offering a 20% discount on all Prepkits. A user can select from extensive selection of over 200 PrepKits to help prepare for their IT certification exam(s).

Duration of Sale: Monday, April 8, 2010 and ends on April 20, 2010.

To avail sale price: Type SPRING as the discount code during checkout

Full details of the sale can be found at: http://www.ucertify.com/blog/celebrate-your-spring-with-ucertifys-spring-sale.html

About uCertify

uCertify is committed to serving its customers with innovative, reliable, and high-quality products through continuous research and development, keeping in mind the trends and changes for each certification exam. As you know that uCertify also backs its entire range of PrepKits with a 100% pass guarantee. In the unlikely event, if a user do not pass your exam in the first attempt, uCertify refunds the entire amount - no questions asked! It's the best guarantee in the business!

Mapping Conceptual Model Function to Complex Type in Entity Framework 4.0

Wed, 07 Apr 2010 11:57:00 PDT

Introduction

You might hear of KiGG, the open source project that is currently live as http://dotnetshoutout.com. I wanted to expose part of KiGG data as an OData Service for read only. But I figured out that exposing raw KiGG schema might not be useful. So I had to choose between 2 options that were up to my mind:

Build some views on the physical store -database-. Create a new entity data model for those views and use the new data model context for DataServiceContext.
Use Entity Framework 4.0 conceptual model function feature with complex types to simulate views. It’s like building views on the conceptual model itself and not the store model.

I picked the 2nd option. The sample downloadable sample is available at the end of this post.

KiGG Entity Data Model

I needed to expose “most viewed” stories from the data model in a simple way. However, the query seemed to be complex when using LINQ over OData or through a URL.

The query will require retrieving stories from Stories entity set and count each story view in StoryViews entity set.

To expose this through an OData service, I thought it would be better to make it as service operation “MostViewed” that will return an IQueryable of a certain complex type.

Creating Complex Type StorySummary

At the beginning I used Entity Framework designer to create a complex type called StorySummary with 3 properties, Title, Url and Views as shown in the next figure.

And here is another cool post by Julie Lerman “Complex Types in the EDM Designer in EF4 and a look at updating complex types in code”

LINQ to Entities Vs Conceptual Model Functions

One question might raise here! Why use eSQL with Conceptual Model functions and not using LINQ to Entities directly?

In my case here, the answer is very straight forward. I cannot use LINQ to Entities here, because constructing Complex Type inside LINQ to Entities query is not support so far. That means I’ll need to construct anonymous type instead! And Of course I cannot use IQueryable<Anonymous type> as a return result for my service operation.

On the other hand, Entity SQL (ESQL) gives a good facility to construct complex types inside a query. And better, I can put this as reusable Conceptual Model Function that can be invoked inside LINQ to Entities queries -How to: Call Model-Defined Functions in Queries (LINQ to Entities)-. And also can be invoked as ObjectContext method -How to: Call Model-Defined Functions as Object Methods (LINQ to Entities)-

Create Conceptual Model Function for StorySummary

To create a conceptual model function I’ll need to switch to XML view of my EDMX.

Right click on the model and select “Open With…” option
From the dialog window “Open With” select “Automatic Editor Selector (XML)” option

Scroll to the end of your conceptual model as show in the following screenshot

Note that It's mandatory to place the parameters in the same order as the properties of the class are declared as shown in the above code snippet figure.

Create your model function using Function element as the following:

 <Function Name="GetMostViewedStories" 
          ReturnType="Collection(Kigg.Model.StorySummary)">
  <DefiningExpression>
    SELECT 
      VALUE(Kigg.Model.StorySummary(innerQ.Title, innerQ.Url, innerQ.Views))
    FROM
    (
      SELECT
      sv.Story.Title as Title,
      sv.Story.Url as Url,
      Count(sv.StoryId) as Views
      FROM KiggContainer.StoryViews as sv
      GROUP BY sv.Story.Title,sv.Story.Url ORDER BY Views DESC
    ) as innerQ
  </DefiningExpression>
</Function>
 

In Name attribute I specified the Edm function name. And in ReturnType I specified the expected result type of this function. Because this function isn’t scalar, and it should return a list of result, I specified the return type to be “Collection(Kigg.Model.StorySummary)”.

Inside Function element I added DefiningExpression element. Its content will be the body of the model function. In my case the Entity SQL query that will return result set of StorySummary with views count calculated for each story as shown in the query above.

HINT: I have an important hint about constructing Complex Type inside EntitySql. In the screenshot above, note the arrows (1, 2 & 3) made beside StorySummary complex type properties. Then in the Entity SQL query, note the sequence of parameters passed to StorySummary constructor inside the query. This sequence must match the same sequence of the defined properties of the complex type.

The generated SQL of the above query is this:

 SELECT 
1 AS [C1], 
[GroupBy1].[K1] AS [Title], 
[GroupBy1].[K2] AS [Url], 
[GroupBy1].[A1] AS [C2]
FROM ( SELECT 
    [Extent2].[Title] AS [K1], 
    [Extent2].[Url] AS [K2], 
    COUNT([Extent1].[StoryId]) AS [A1]
    FROM  [dbo].[StoryView] AS [Extent1]
    INNER JOIN [dbo].[Story] AS [Extent2] ON [Extent1].[StoryId] = [Extent2].[Id]
    GROUP BY [Extent2].[Title], [Extent2].[Url]
  )AS [GroupBy1]
 

To be able to invoke this model function from LINQ to Entities, I’m going to create a function in my generated ObjectContext that will map to this function as the following:

 public partial class KiggContainer
{
    [EdmFunction("Kigg.Model", "GetMostViewedStories")]
    public IQueryable<StorySummary> GetMostViewedStories()
    {
 
        return QueryProvider.CreateQuery<StorySummary>(
            Expression.Call(Expression.Constant(this),
            (MethodInfo)MethodBase.GetCurrentMethod()));
    }
}
 

For more details about this please refer to How to: Call Model-Defined Functions as Object Methods (LINQ to Entities)

Calling Conceptual Model Function inside OData Service Operation

This is very simple here is the code snippet:

 [WebGet(RequestFormat = WebMessageFormat.Json, 
        ResponseFormat = WebMessageFormat.Json, 
        BodyStyle = WebMessageBodyStyle.Wrapped)]
public IQueryable<StorySummary> MostViewed()
{
    return CurrentDataSource.GetMostViewedStories();
}
 

Invoking this method is as simple as this:
“http://localhost:2274/KiggOData.svc/MostViewed” Or
“http://localhost:2274/KiggOData.svc/MostViewed?$filter=Views ge 6”

And filtering will be applied on server side, and you can check that using SQL Server profiler.

References

Conclusion

This post was about Conceptual Model Function, and how it could be useful to create reusable views using Entity SQL the can return result set of complex type. Also we explored how to invoke EDM functions using LINQ to Entities and use it with OData Service Operation.

I hope this post was useful and you enjoyed it.

Attachments: EF4 Conceptual Model Functions with Complex Types (EF4ModelDefinedFunctionWithComplexTypes.zip)