Some Queries using Language integrated Query ( LINQ ).

Let Us perform some queries using Linq:

1. Retrieve all records from database

   sampleDataContext sdc = new sampleDataContext();

   //var data = from d in sdc.ToyShops select d ;(retrieve all records)

   var data = from d in sdc.ToyShops select new { id=d.toyId,name=d.toyname};// retrieve selected column

   dataGridView1.DataSource = data;

2. Update records from database

    sampleDataContext sdc = new sampleDataContext();

    ToyShop ts = sdc.ToyShops.Single(c => c.toyId == Convert.ToInt32(textBox1.Text));

    ts.toyname = textBox2.Text;

    sdc.SubmitChanges();

    MessageBox.Show("records Updated successfully !!");

3. Delete records from database

    sampleDataContext sdc = new sampleDataContext();

    ToyShop ts = sdc.ToyShops.Single(c => c.toyId == Convert.ToInt32(textBox1.Text));

    sdc.ToyShops.DeleteOnSubmit(ts);

    sdc.SubmitChanges();

    MessageBox.Show("records deleted  successfully !!");

4. Delete records from database

    sampleDataContext sdc = new sampleDataContext();

     ToyShop ts = new ToyShop();

     ts.toyId = Convert.ToInt32(textBox1.Text);

     ts.toyname = textBox2.Text;

     sdc.ToyShops.InsertOnSubmit(ts);

     sdc.SubmitChanges();

     MessageBox.Show("data inserted successfully ");

5. Skip() and Take()

     sampleDataContext sdc = new sampleDataContext();

     var data = (from d in sdc.ToyShops select d).Skip(1).Take(2);

     dataGridView1.DataSource = data;

6. Generate Computable fields using Linq

      sampleDataContext sdc = new sampleDataContext();

      //var data = from d in sdc.ToyShops select d ;(retrieve all records)

      var data = from d in sdc.ToyShops select new { id = d.toyId, name = d.toyname,price=d.price,quantity=d.nofQuantity,netPrice=d.price*d.nofQuantity };

      dataGridView1.DataSource = data;


Note :
Where Toyshop is the name of the Table in your database .