Linq query with different data sources List, Array and SQL

25 Oct 2016

Document by Ganesan – Ganesanva@hotmail.com – + 919600370429

Create StudentDetails Table in TestDB using the below snippet,

CREATE TABLE [dbo].[StudentDetails] (
[Id] INT IDENTITY (1, 1) NOT NULL,
[StudentName] VARCHAR (50) NULL,
[Age] INT NULL,
[inchargeStudentId] INT NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);

– Create a Console Application
Use SQL to Linq Converter,
http://www.sqltolinq.com/
Click on Generate Linq to SQL Model Files,

Browse a Folder and Click on OK.
Click on Generate Linq to SQL Files,

Convert SQL query to Linq as below,

Age> 24 and StudentName contains ‘Sco’

Screen clipping taken: 10-09-2016 19:21
Self Join in Linq

Right click on the table and select Regenerate Model Files.
Insert the connection below in App.config,

Add StudentDetails.cs and data context file as below,

public class StudentDetails
{
public int Id { get; set; }
public string StudentName { get; set; }
public int? Age { get; set; }
public int? InchargeStudentId { get; set; }
}
public class UsersContext : DbContext
{
public UsersContext(): base(“TestConnection”)
{
}
public DbSet<StudentDetails> studentDbset { get; set; }
}

Insert the below Code snippet in Console,

class Program
{
private static UsersContext db = new UsersContext();
static void Main(string[] args)
{
/* Getting the Student Db Collection from DB */
List<StudentDetails> obj= db.studentDbset.ToList();
foreach (var item in obj)
{
Console.WriteLine(“Student Name” + “\t” + item.StudentName + “\t” + “Age:” + item.Age);
}
/* Getting the Student Db Collection for Age>24 from DB */
Console.WriteLine(“———————————————————-“);
Console.WriteLine(“Printing Age > 24”);
var query =
from StudentDetails1 in db.studentDbset
where
StudentDetails1.Age > 24
select new
{
Id = StudentDetails1.Id,
StudentName = StudentDetails1.StudentName,
Age = StudentDetails1.Age
};
foreach (var r in query)
Console.WriteLine(“Student Name” + “\t” + r.StudentName + “\t” + “Age:” + r.Age);
/* Getting the Student Db Collection for Age>24 from DB */
Console.WriteLine(“———————————————————-“);
Console.WriteLine(“Printing Age > 24 && Student Name contains Sco”);
var query1 =
from StudentDetails1 in db.studentDbset
where
StudentDetails1.Age > 24 &&
StudentDetails1.StudentName.Contains(“Sco”)
select new
{
Id = StudentDetails1.Id,
StudentName = StudentDetails1.StudentName,
Age = StudentDetails1.Age
};
foreach (var r in query1)
Console.WriteLine(“Student Name” + “\t” + r.StudentName + “\t” + “Age:” + r.Age);
/* Getting the Student Db Collection for getting Incharge on Self join from DB */
Console.WriteLine(“———————————————————-“);
Console.WriteLine(“Printing self join for Students Lead”);
var query2 =
from s in db.studentDbset
join s1 in db.studentDbset on new { InchargeStudentId = s.InchargeStudentId.Value } equals new { InchargeStudentId = s1.Id }
select new
{
s.Id,
s.StudentName,
s.Age,
incharge = s1.StudentName
};
foreach (var r in query2)
Console.WriteLine(“Student Name” + “\t” + r.StudentName + “\t” + “Age:” + r.Age + “\t” + “Incharge:” + r.incharge);
/* Getting the Collection from DB */
Console.WriteLine(“———————————————————-“);
Console.WriteLine(“Printing from Array”);
string[] ary = new string[] { “Jan”, “Feb”, “Mar”, “Apr”, “May”, “Jun”, “Jul”, “Aug”, “Sep”, “Oct”, “Nov”, “Dec” };
var res = from months in ary
where months.StartsWith(“J”)
select new { MonthStartWith_J = months };
foreach (var r in res)
Console.WriteLine(“Month:” + “\t” + r.MonthStartWith_J);
/* Getting the Collection from DB */
Console.WriteLine(“———————————————————-“);
Console.WriteLine(“Printing from Collection”);
List<string> objstring = new List<string>();
objstring.Add(“Yahooo”);
objstring.Add(“Google”);
objstring.Add(“HCL”);
var obj1 = from company in objstring where company.StartsWith(“Goo”)
select new { companyStartWith_Goo = company };
foreach (var r in obj1)
Console.WriteLine(“Month:” + “\t” + r.companyStartWith_Goo);
Console.ReadLine();
}
}

The Output as below,

Screen clipping taken: 10-09-2016 21:34
Click below for download,
https://1drv.ms/u/s!ArddhCoxftkQg6hZlD6medX1rPn9pw
Reference
http://www.dotnetlearners.com/linq/linq-to-string-array-with-example.aspx

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Linq query with different data sources List, Array and SQL

Document by Ganesan – Ganesanva@hotmail.com – + 919600370429

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