LINQ (Language Integrated Query) - Part 2
This is second part of the ‘LINQ’ series
posts that I have started from here. And in this post, you will see some quick
examples on LINQ title.
Very simple examples on LINQ so far, stay tuned, you will find more
stuff.
As I said in previous post, with LINQ you
just need to perform three distinct actions: Obtain the Data Source, Create the
query and Execute the query, you will notice it in sample programs given below.
We will create Console Apps and test various LINQ concepts. I will walk through
very simple programs here and in coming part will dig in depth.
LINQ has a great power of querying on any
source of data that could be the collections of objects (in memory data, like
array), SQL Database or XML files. We can easily retrieve data from any object
that implements the IEnumerable<T> interface.
LINQ
to Array:
Let’s look at a Program to find Even Number
using LINQ to Array.
If you execute above program, you will get ‘2
4 6 8 10’ as output. You will notice 3 actions above, these actions will be
changed always depending upon our project requirement. In above example, ‘data
source’ was an array that implicitly supports the generic IEnumerable<T>
interface.
LINQ
to XML:
Now, let’s move on to take a look at LINQ to
XML example and find student names from XML file. LINQ to XML loads an XML
document into a query-able XElement type and then IEnumerable<XElement>
loads the query result and using foreach loop we access it.
Student.xml File
LINQ
to SQL:
In LINQ to SQL, we firstly create an
object-relational mapping at design time either manually or by using the Object
Relational Designer. Then, we write queries against the objects, and at
run-time LINQ to SQL handles the communication with the database.
Now, let’s look at the sample program.
good post)))
ReplyDeletethanks frnd.
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