Table Of ContentBuilding Interactive Queries
with LINQPad
Learn how to query databases interactively using
LINQ and LINQPad
Sébastien Finot
professional expertise distilled
P U B L I S H I N G
BIRMINGHAM - MUMBAI
Building Interactive Queries with LINQPad
Copyright © 2013 Packt Publishing
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First published: July 2013
Production Reference: 1190713
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Cover Image by Prashant Timappa Shetty ([email protected])
Credits
Author Project Coordinator
Sébastien Finot Akash Poojary
Reviewers Proofreader
Alexandre Brisebois Joel Johnson
Antonio Rodriguez
Indexer
Hemangini Bari
Acquisition Editor
Aarthi Kumaraswamy
Production Coordinator
Conidon Miranda
Commissioning Editor
Shaon Basu
Cover Work
Conidon Miranda
Technical Editors
Dipika Gaonkar
Dennis John
Menza Mathew
Nitee Shetty
About the Author
Sébastien Finot, fascinated by computer science on the whole (but with a specific
dedication to application development and games), has been working for more than
15 years for both small and large worldwide companies at various technical positions,
ranging from developer to technical project manager, and for the last five years, as the
CTO of communication agencies. He is also pursuing an entrepreneur path with his
own company (in France) where he can work on fun and innovative projects. Sébastien
has been using LINQ for five years now and has been a LINQPad user for almost
as long.
Sébastien can be reached by any means listed on this website: http://about.me/
sebastienf.
I would like to thank my parents for all the love and the support
they give me all the time and for teaching me that one can achieve
anything if motivated enough. This book couldn't have been written
without the support of my fantastic wife (love you!). Big thanks
also for the technical reviewers of this book whose suggestions and
remarks enhanced the overall quality. Finally, my thanks to Packt
Publishing for giving me the opportunity to write this book and live
that interesting adventure.
About the Reviewers
Alexandre Brisebois, Windows Azure MVP and a member of the Windows
Azure Community Experts, helps you to make informed decisions. He provides
both technical and architectural guidance for Windows Azure solutions. Being a
strong believer in clean code and best practices, he employs agile practices in order
to produce maintainable solutions. Exploring .NET since 2002, his passion for
new technologies has driven him to work for companies such as Pratt & Whitney,
Canada, Air France, and CGI. After two years in Paris as a .NET consultant, he
is now part of Runatserver (www.runatserver.com), a team of highly qualified,
certified experts specializing in the latest technology.
If you would like reach out to Alexandre about the book or Windows Azure, feel free
to contact him via twitter (@Brisebois) or his blog (http://alexandrebrisebois.
wordpress.com).
Antonio Rodriguez is a Software Engineer who likes solving interesting
problems, and tinkering with different technologies and programming languages.
He occasionally documents his experiments on his blog (http://www.xhroot.com).
When he is not writing code, he enjoys spending time with his wife Ping and his
son Isaac.
Antonio holds a Bachelor's degree in Computer Engineering from the Georgia
Institute of Technology.
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Table of Contents
Preface 1
Chapter 1: Discovering LINQPad 5
Downloading and installing LINQPad 5
Editions available 6
Look and feel of LINQPad 6
The File menu 7
The Edit menu 9
The Query menu 12
The Help menu 14
Configuring LINQPad 14
The Editor tab 15
The Query tab 15
The Results tab 15
The Folders tab 15
The Web proxy tab 15
The Advanced tab 15
Summary 16
Chapter 2: Coding in LINQPad 17
Writing your first LINQPad query 17
Query types 19
The C#/F#/VB expression 19
The C# and VB statement 20
The C#, F#, and VB programs 21
SQL/ESQL 22
Referencing additional assemblies 22
Adding it manually 22
Adding it with NuGet 23
Referencing additional namespaces 24
Table of Contents
LINQPad’s Dump() method 25
Summary 28
Chapter 3: Learning LINQ's Basics 29
The fundamentals of LINQ 29
The purpose of LINQ 30
A LINQ query 31
The standard version 31
The LINQ version 34
Query operators 37
Chaining calls 37
One LINQ, two syntaxes 38
Summary 39
Chapter 4: Discovering LINQ Query Operators 41
Defining LINQ to objects 41
Query operators 42
Quantifier operations 42
The Any() query operator 43
The All() query operator 44
The Contains() query operator 45
Filtering operations 45
The Where() query operator 46
The OfType() query operator 47
Sorting operations 50
The OrderBy() and OrderByDescending() query operators 50
The ThenBy() and ThenByDescending() query operators 54
The Reverse() query operator 55
Partitioning operations 56
The Take() and TakeWhile() query operators 56
The Skip() and SkipWhile() query operators 58
Summary 60
Chapter 5: Database and Relational Data 61
Introducing LINQ to SQL 61
Setting up a database 61
Adding a connection to LINQPad 62
Interacting with the database 64
Looking into the categories 64
Filtering the categories 66
Element operations 67
The First() and FirstOrDefault() query operators 67
The Single() and SingleOrDefault() query operators 67
The Last() and LastOrDefault() query operators 68
The ElementAt() and ElementAtOrDefault() query operators 68
[ ii ]
Table of Contents
Conversion operations 69
The ToArray() and ToList() query operators 69
The ToDictionary() and ToLookup() query operators 69
Deferred execution 70
Grouping operations 71
The GroupBy() query operator 71
Working with relational data 72
Interactive navigation with LINQPad 74
Projection operations 76
The Select() query operator 76
The SelectMany() query operator 78
Inserting, updating, and deleting data 78
Adding a new entry to the database 78
Updating entries from the database 79
Deleting data from the database 80
Views and Stored Procedures 80
Acknowledging LINQ to SQL limits 81
Summary 82
Chapter 6: Using Other Data Sources 83
Handling XML 83
Creating and querying an XML fragment 83
Aggregation operations 86
The Average() and Sum() query operators 86
The Max() and Min() query operators 86
The Count() and LongCount() query operators 86
Using XPath 87
Other operations 87
Discovering Entity Framework 88
Setting up the context 88
Running your first Entity Framework query 90
Join operations 92
The Join() query operator 92
The GroupJoin() query operator 93
Interacting with WCF Data Services 94
Adding a connection to a service 94
Making your first request to the service 95
Summary 96
Chapter 7: Getting More Out of LINQPad 97
Customizing LINQPad 97
Customizing the results pane 97
Writing a custom visualizer 102
[ iii ]
