How to select all data from table (SQL To LINQ)

How to select all data from table (SQL To LINQ):

The following code snippet shows you how you can query direct to SQL Server and in its comparison how you can query using LINQ and get all data.

This is the connection string which let you connect to the server:

               Data Source = "Your Server Name"

               Initial Catalog = "The name of your database"

              Integrated Security = "true" for getting your credentials automatic to your current login account in windows, in this way you don't have to use user id and password while establishing connection with SQL server.

public static string conString = @"Data Source =  MOAVIA_OSAMA-PC\SQLEXPRESS;Initial Catalog = MyFirst ; Integrated Security = true";

In SQL we write the following query to select all data from a particular table, here we are selecting data from table Customer which contains ID, Name and Address columns in it.

   string SQLQuery = "SELECT * FROM Customer";

Now, we would execute this query and return all table from database to store in table. The following GetDataTable() function execute the query and returns the data in table:

public static DataTable GetDataTable(string query)

{

                    

  SqlConnection SQLCon = new SqlConnection(conString);

  SqlCommand cmd = new SqlCommand(query, SQLCon);

  DataTable table = new DataTable();

  SqlDataAdapter da = new SqlDataAdapter(cmd);

  da.Fill(table); // and filling the table against the query

          

  return table;

}

In the following statement we executed the query and store/show the data in DataGridView:

dataGridView1.DataSource = getDataTable(SQLQuery);

Result In DataGridView:

Now In LINQ:

The following is the class generated when you add "Linq to SQL classes" to project, which takes an argument of connection string:

DataClasses1DataContext dc = new DataClasses1DataContext(conString);

The following query also selects all data from table Customer:
 

var LINQuery =

         from Customer c in dc.Customers

         select c;

In the following statement we executed the query and store/show the data in DataGridView:

dataGridView1.DataSource = LINQuery;