Welcome!

Microsoft Cloud Authors: Kevin Benedict, Pat Romanski, Liz McMillan, Lori MacVittie, Elizabeth White

Related Topics: Microsoft Cloud

Microsoft Cloud: Article

Book Review: Pro LINQ

Language Integrated Query in C# 2008

As promised by the author, this book starts with code (“Hello LINQ”), ends with code (a query joining database data with XML data), and is code-heavy in the middle. All the code runs and the output is listed in the book. The code snippets you can steal will quickly recoup the price of the book.

It’s divided into five parts: Introduction, LINQ to Objects, LINQ to XML, LINQ to DataSet, and LINQ to SQL.

Part One has two chapters. In the first chapter, “Hello LINQ,” the author shows how to use LINQ to query XML and SQL databases, and adds that LINQ can also work with DataSets, object, and Entities. He also points out that LINQ (Language Integrated Query) is more of a data-iteration engine, but that Microsoft didn’t want to name its hot new technology “DIE”! Yep, Joseph has a sense of humor, and it pops up from time to time in this book.

The second chapter covers the language enhancements in C# and VB.NET to support LINQ. Note I didn’t specify the version of C# or VB.NET. That’s because the building blocks of LINQ have been being added in one by one since .NET version 2.0. In some cases the author goes into some detail on what problem the language addition was meant to address, and how the addition addresses the problem. The chapter ends with eight pages of details on how the compiler translates LINQ into C# or .NET code. Joseph admits that you’re about as likely to need this information as you need to know what machine code is generated for a foreach loop, but I find it interesting, and I’m impressed that he dug the information up.

The second part covers LINQ to objects, serving also as an overall introduction to LINQ. After a quick intro to LINQ in Chapter Three, Chapter Four covers deferred operations, so-called because they return a type of IEnumerable<T> that will be iterated through at a later time. Chapter Five covers non-deferred types, so-called because they immediately return values of types other than IEnumerable<T>. An example of this would be conversion routines such as ToList.

Part three covers LINQ to XML, with Chapter Six kicking things off with a description of creating a simple XML document using DOM to show the amount of code involved so we can see how big an improvement LINQ to XML is. Chapter Seven covers the LINQ XML API, and discusses the “Halloween” problem, so-called because it was first discussed by experts on Halloween. The problem occurs if part of an XML document is modified while a LINQ query is still iterating over it. Chapter Eight covers LINQ-to-XML operators, such as “DescendantNodes,” which return a sequence containing the descendant nodes of each element or document. Chapter Nine covers transformations and validation. If you plan on using LINQ and XML, the code snippets in this section are worth their weight in gold.

Part four consist of two very short chapters covering LINQ to DataSet. The author chose to cover LINQ DataSet operations before covering LINQ to SQL because LINQ to SQL only works with Microsoft SQL Server, where you can retrieve DataSets from almost any database and then use LINQ to query the results. Chapter 10 covers DataRow and DataTable operators. Chapter 11 quickly covers typed DataSets. As I said, it’s a short section.

The fifth and final part covers LINQ to SQL. Chapter 12 is another short chapter that introduces us to LINQ to SQL. The author points out that most technologies that link relational databases to business classes lose the ability to do queries against the classes. He then discusses a bit about how entity-mapping classes solve this problem by allowing LINQ to run queries and even updates against classes created from SQL databases.

In Chapter 13 the author gives tips and discusses tools. Joseph points out that if we don’t understand his tips now, he’s done his job, because he wants to give us tips before we need them, not after we’ve learned we need them the hard way. The tools he discusses are SQLMetal and Object Relational Designer. Both are included in the .NET 3.5 Framework.

Chapter 14, “LINQ to SQL Database Operations,” is described as “a whirlwind tour of standard database operations.” It covers such things as how LINQ-to-SQL queries are executed in the database, and the issues caused by the fact that LINQ stands for “Language Integrated Query,” where queries are written as close to the programming language (C# in our case) as possible, but have to be translated into true SQL for execution. This, for example,

where c.CustomerID.TrimEnd(‘k’) == “Lazy”

throws an error because TrimEnd is not valid SQL.

where c.CustomerID == “Lazy”. TrimEnd(‘k’)

executes without error because TrimEnd is a valid .NET function. Understand the difference? If not, buy the book and let Joseph explain it. Simply put, in this case the left side is evaluated by SQL and the right side is evaluated by C#.

Chapter 15 covers LINQ-to-SQL entity classes, including generating entity classes, extending entity classes with partial methods, and important System.Data.Linq API classes. Chapter 16 is a long chapter covering the details of the DataContext class, including example code for many of its functions. Chapter 17 covers detecting and resolving concurrency conflicts including pessimistic concurrency and transactions. The final chapter, Chapter 18, covers views, entity class inheritance, and more information on transactions.

This is a well-written book, full of tips and traps, with enough source code snippets to make it worth buying for that reason alone. It’s value-packed with information from someone who clearly knows what he’s talking about. It’s one of the better books I’ve seen on LINQ and will be a welcome addition to my bookshelf.

Title: Pro LINQ: Language Integrated Query in C# 2008
Author: Joseph C. Rattz, Jr.
Publisher: Apress
ISBN: 978-1-59059-789-7
Price: U.S. $44.99

More Stories By Dennis Hayes

Dennis Hayes is a programmer at Georgia Tech in Atlanta Georgia where he writes software for the Adult Cognition Lab in the Psychology Department. He has been involved with the Mono project for over six years, and has been writing the Monkey Business column for over five years.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


IoT & Smart Cities Stories
All in Mobile is a place where we continually maximize their impact by fostering understanding, empathy, insights, creativity and joy. They believe that a truly useful and desirable mobile app doesn't need the brightest idea or the most advanced technology. A great product begins with understanding people. It's easy to think that customers will love your app, but can you justify it? They make sure your final app is something that users truly want and need. The only way to do this is by ...
Digital Transformation and Disruption, Amazon Style - What You Can Learn. Chris Kocher is a co-founder of Grey Heron, a management and strategic marketing consulting firm. He has 25+ years in both strategic and hands-on operating experience helping executives and investors build revenues and shareholder value. He has consulted with over 130 companies on innovating with new business models, product strategies and monetization. Chris has held management positions at HP and Symantec in addition to ...
Dynatrace is an application performance management software company with products for the information technology departments and digital business owners of medium and large businesses. Building the Future of Monitoring with Artificial Intelligence. Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more busine...
DXWorldEXPO LLC announced today that Big Data Federation to Exhibit at the 22nd International CloudEXPO, colocated with DevOpsSUMMIT and DXWorldEXPO, November 12-13, 2018 in New York City. Big Data Federation, Inc. develops and applies artificial intelligence to predict financial and economic events that matter. The company uncovers patterns and precise drivers of performance and outcomes with the aid of machine-learning algorithms, big data, and fundamental analysis. Their products are deployed...
The challenges of aggregating data from consumer-oriented devices, such as wearable technologies and smart thermostats, are fairly well-understood. However, there are a new set of challenges for IoT devices that generate megabytes or gigabytes of data per second. Certainly, the infrastructure will have to change, as those volumes of data will likely overwhelm the available bandwidth for aggregating the data into a central repository. Ochandarena discusses a whole new way to think about your next...
CloudEXPO | DevOpsSUMMIT | DXWorldEXPO are the world's most influential, independent events where Cloud Computing was coined and where technology buyers and vendors meet to experience and discuss the big picture of Digital Transformation and all of the strategies, tactics, and tools they need to realize their goals. Sponsors of DXWorldEXPO | CloudEXPO benefit from unmatched branding, profile building and lead generation opportunities.
Cell networks have the advantage of long-range communications, reaching an estimated 90% of the world. But cell networks such as 2G, 3G and LTE consume lots of power and were designed for connecting people. They are not optimized for low- or battery-powered devices or for IoT applications with infrequently transmitted data. Cell IoT modules that support narrow-band IoT and 4G cell networks will enable cell connectivity, device management, and app enablement for low-power wide-area network IoT. B...
The hierarchical architecture that distributes "compute" within the network specially at the edge can enable new services by harnessing emerging technologies. But Edge-Compute comes at increased cost that needs to be managed and potentially augmented by creative architecture solutions as there will always a catching-up with the capacity demands. Processing power in smartphones has enhanced YoY and there is increasingly spare compute capacity that can be potentially pooled. Uber has successfully ...
SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
When talking IoT we often focus on the devices, the sensors, the hardware itself. The new smart appliances, the new smart or self-driving cars (which are amalgamations of many ‘things'). When we are looking at the world of IoT, we should take a step back, look at the big picture. What value are these devices providing. IoT is not about the devices, its about the data consumed and generated. The devices are tools, mechanisms, conduits. This paper discusses the considerations when dealing with the...