Introduction to LINQ with C# programming

1. Introduction to LINQ
Pakorn Weecharungsan

2. Contents
 What is LINQ?
 LINQ Providers
 Fundamental LINQ syntax

3. What is LINQ?
 LINQ (Language Integrated Query) is a
new feature of C# and Visual Basic .NET t
hat integrates into these languages the abi
lity to query data

4. What is LINQ?

5. LINQ Providers
 LINQ to Objects
 LINQ to XML
 LINQ Support for ADO.NET
LINQ to SQL
LINQ to Datasets
LINE to Entities

6. Query Syntax and Method Syntax
 Query syntax is a declarative form that
looks very much like an SQL statement.
Query syntax is written in the form of
query expressions
 Method syntax is an imperative form,
which uses standard method invocations.
The methods are from a set called the
standard query operators

7. Query Syntax and Method Syntax

8. The Structure of Query
Expressions

9. The from clause
 The from clause specifies the data
collection that is to be used as the data
source. It also introduces the iteration
variable

10. The join clause
 The join clause in LINQ is much like the
JOIN clause in SQL

11. The where Clause
 The where clause eliminates items from
further consideration if they don’t meet the
specified condition. The syntax of the
where clause is the following

12. The where Clause

13. The orderby Clause
 The orderby clause takes an expression
and returns the result items in order
according to the expression

14. The orderby Clause

15. The group Clause
 The group clause groups the selected
objects according to some criterion. For
example, with the array of students in the
previous examples, the program could
group the students according to their
majors

16. The group Clause

17. The Standard Query Operators
 The standard query operators comprise a
set of methods called an application
programming interface (API) that lets you
query any .NET array or collection

18. The Standard Query Operators