Set Operations in LINQ

Set Operations in LINQ

We use following set operations in LINQ:-

Distinct

Distinct remove redundancy and show the unique records.

Figure 1

For example:-

int[] techaltum = { 1, 2, 3, 4, 3, 4, 5, 19, 89, 4, 8, 2 };

        IEnumerable<int> res = techaltum.Distinct();

        Response.Write("Result after Distinct <br/>");

        foreach (int data in res)

        {

            Response.Write(data+"<br/>");

              

        }

LINQ Hour 5 -1 Aggregate function in LINQ

Written By:-Isha Malhotra 

Our Website:-www.techaltum.com

Aggregate function using LINQ

We use many aggregate functions like sum, count, average, min, and max. In LINQ we can use this function in the following manner:-

SUM

If we want to perform sum aggregate function then we will implement the following queries:-

Sum with array

int[] marks = new int[] { 23, 45, 78, 90, 56, 89, 10, 32 };

        //simple sum without condition

        int res = marks.Sum();

        //sum with condition

        int res_with_where = marks.Where(cond => cond > 50).Sum();

      

        Response.Write("Sum without condition= " + res + "<br/>");

        Response.Write("Sum with condition="+ res_with_where+"<br/>");

Output of this code as follows:-

Figure 1

LINQ Hour 5 - Queries using LINQ

Written By:-Isha Malhotra 

Our Website:-www.techaltum.com

Perform different functionality (QUERY) using LINQ

As in the previous article I already discussed about select, insert, update and delete. I also discussed with where clause, order by, grouping. In this hour I will discuss about different operation which we can perform using LINQ. As we know we can perform this functionality on array, generics, database, xml etc. so here I am taking the example of array, generics and database. I will discuss xml separately.  

To work with this functionality I am taking the following source:-

Array

Using following int array:-

int[] marks = new int[] { 23, 45, 78, 90, 56, 89, 10, 32 };

Generics:-

Using following class to implement generics:-

public class data

{

    public int roll_no;

    public string student;

    public int per;

}

And following list:-

List<data> dt = new List<data>()

        {

            new data{roll_no=1, student="isha", per=100},

            new data{roll_no=2, student="neha", per=89},

            new data{roll_no=3, student="rahul", per=34}

        };

Database

Using following table:-

Figure 1

And create its class to mapping this table which is as follows:-

[Table(Name="prod_rep")]

public class Class1

{

   

    [Column]

    public int id;

    [Column]

    public int prod_year;

    [Column]

    public string dept;

    [Column]

    public int no_of_prod;

}

click on the following link to perform different functionality:-

Part 1 Aggregate function in LINQ

Part 2 Sorting in LINQ

Part 3 Take / TakeWhile and Skip / SkipWhile

LINQ Training - Hour 1

Written By:-Isha Malhotra(malhotra.isha3388@gmail.com)
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LINQ-Hour 1

Language Integrated Query introduced in .net framework 3.5. LINQ integrated accessibility of data and query into language. LINQ makes easier to work with data.

Advantage of LINQ

Earlier when we connect to database, we used SQL queries as text like if we have to select any data from table then we write following queries:-

“select * from Table_name”

This query will be passed as text and if this query has some syntax error then it will be showed when this query will be executed means at runtime. But in LINQ at the time of compile time all syntax checked as it integrate query writing in our language(C# or Vb.net)

Query writing in LINQ

LINQ allows us to write query against all data whether it comes from array, database, XML etc.  This is the best feature of LINQ.

Before going deep into LINQ lets run some basic queries in LINQ using arrays and try to understand the syntax of LINQ