Entity & Relation (Foreign Key , CasCade , Delete , Update) (LINQ, Entity Framework)

        private void frmMain_Load(object sender, EventArgs e)
        {
            // Create new entities Object
            using (var db = new myDatabaseEntities())
            {
                // Get data from CUSTOMER
                var ds = (from c in db.CUSTOMER
                          select new
                          {
                              CusID = c.CUSTOMER_ID,
                              CusName = c.NAME,
                              CusCountryName = c.COUNTRY.COUNTRY_NAME,
                          }).ToList();

                // Assign to DataGridView
                if (ds.Count() > 0)
                {
                    this.myDataGridView.DataSource = ds;
                }
            }
        }

    Private Sub frmMain_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' Create new entities Object
        Using db = New myDatabaseEntities()
            ' Get data from CUSTOMER
            Dim ds = (From c In db.CUSTOMER Select New With { _
                    .CusID = c.CUSTOMER_ID, _
                    .CusName = c.NAME, _
                    .CusCountryName = c.COUNTRY.COUNTRY_NAME _
                }).ToList()

            ' Assign to DataGridView
            If ds.Count() > 0 Then
                Me.myDataGridView.DataSource = ds
            End If
        End Using
    End Sub

        private void frmMain_Load(object sender, EventArgs e)
        {
            // Create new entities Object
            using (var db = new myDatabaseEntities())
            {

                // CustomerID C001
                string strCustomerID = "C001";

                // Get data from CUSTOMER
                var cus = (from c in db.CUSTOMER
                           where c.CUSTOMER_ID == strCustomerID
                           select c).FirstOrDefault();

                // if found item rows
                if (cus != null)
                {
                    // Result 1 and 2
                    this.lblResult1.Text = string.Format("Customer ID : {0}", cus.CUSTOMER_ID); // Get CustomerID
                    this.lblResult2.Text = string.Format("Country : {0}", cus.COUNTRY.COUNTRY_NAME); // Get Country Name

                    // Get Audit
                    var audit = (from c in cus.AUDIT
                                 select new
                                 {
                                     c.AUDIT_ID,
                                     c.LOG_DATE,
                                     c.USED,
                                 }).ToList();
                    // Assign to DataGridView
                    if (audit.Count() > 0)
                    {
                        this.myDataGridView.DataSource = audit;
                    }
                }
            }
        }

    Private Sub frmMain_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ' Create new entities Object
        Using db = New myDatabaseEntities()

            ' CustomerID C001
            Dim strCustomerID As String = "C001"

            ' Get data from CUSTOMER
            Dim cus = (From c In db.CUSTOMER
                       Where c.CUSTOMER_ID = strCustomerID Select c).FirstOrDefault()

            ' if found item rows
            If cus IsNot Nothing Then
                ' Result 1 and 2
                Me.lblResult1.Text = String.Format("Customer ID : {0}", cus.CUSTOMER_ID)
                ' Get CustomerID
                Me.lblResult2.Text = String.Format("Country : {0}", cus.COUNTRY.COUNTRY_NAME)
                ' Get Country Name
                ' Get Audit
                Dim audit = (From c In cus.AUDIT Select New With { _
                    c.AUDIT_ID, _
                    c.LOG_DATE, _
                    c.USED _
                }).ToList()
                ' Assign to DataGridView
                If AUDIT.Count() > 0 Then
                    Me.myDataGridView.DataSource = AUDIT
                End If
            End If
        End Using
    End Sub