private static void ShowLinqToEntities()
{
var ef4TestEntities = new EF4TestEntities();
var customerNames = from cn in ef4TestEntities.CustomerNames
select cn;
var shortNames = from cn in ef4TestEntities.CustomerNames
select new { First = cn.FirstName, Last = cn.LastName };
var spatialPoints = from sp in ef4TestEntities.SpatialPoints
select new { Id = sp.Id, X = sp.X, Y = sp.Y };
// Display all initially existing data records
foreach (var cn in customerNames)
{
Console.WriteLine("Customer: {0} {1} {2} {3}", cn.CustomerId, cn.FirstName, cn.LastName, cn.EmailAddress);
}
foreach (var sn in shortNames)
{
Console.WriteLine("Customer (short): {0} {1}", sn.First, sn.Last);
}
foreach (var sp in spatialPoints)
{
Console.WriteLine("Point: {0} {1} {2}", sp.Id, sp.X, sp.Y);
}
// Create new baseline for data within the database
foreach (var cn in customerNames)
{
ef4TestEntities.CustomerNames.DeleteObject(cn);
}
ef4TestEntities.CustomerNames.AddObject(new CustomerName {
FirstName = "Petra", LastName = "Jones", EmailAddress = "*****@*****.**"
});
ef4TestEntities.CustomerNames.AddObject(new CustomerName {
FirstName = "Michael", LastName = "Smith", EmailAddress = "*****@*****.**"
});
ef4TestEntities.CustomerNames.AddObject(new CustomerName {
FirstName = "fn1", LastName = "ln1", EmailAddress = "em1"
});
ef4TestEntities.SaveChanges();
// Display newly created baseline of data
foreach (var cn in customerNames)
{
Console.WriteLine("Customer: {0} {1} {2} {3}", cn.CustomerId, cn.FirstName, cn.LastName, cn.EmailAddress);
}
// Update existing data record
var toUpdate = (from c in ef4TestEntities.CustomerNames
where c.FirstName == "fn1" && c.LastName == "ln1" && c.EmailAddress == "em1"
select c).First();
toUpdate.EmailAddress = "em2";
ef4TestEntities.SaveChanges();
// Display updated data record
foreach (var cn in customerNames)
{
Console.WriteLine("Customer: {0} {1} {2} {3}", cn.CustomerId, cn.FirstName, cn.LastName, cn.EmailAddress);
}
// Delete specific data record
var toDelete = (from c in ef4TestEntities.CustomerNames
where c.FirstName == "fn1" && c.LastName == "ln1" && c.EmailAddress == "em2"
select c).First();
ef4TestEntities.CustomerNames.DeleteObject(toDelete);
ef4TestEntities.SaveChanges();
// Proof that data record has beed deleted
foreach (var cn in customerNames)
{
Console.WriteLine("Customer: {0} {1} {2} {3}", cn.CustomerId, cn.FirstName, cn.LastName, cn.EmailAddress);
}
}
private static void ShowEntityFramework()
{
var allCustomerNames = "SELECT c FROM EF4TestEntities.CustomerNames AS c";
var allValueCustomerNames = "SELECT VALUE c FROM EF4TestEntities.CustomerNames AS c";
var michaelValueCustomerNames = "SELECT VALUE c FROM EF4TestEntities.CustomerNames AS c WHERE c.FirstName = @firstName";
var ef4TestEntities = ConfigurationManager.ConnectionStrings["EF4TestEntities"].ConnectionString;
// All customers as raw DbDataRecords through EntityClient provider
using (var cn = new EntityConnection(ef4TestEntities))
using (var cmd = new EntityCommand(allCustomerNames, cn))
{
cn.Open();
using (var dr = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
{
while (dr.Read())
{
Console.WriteLine(((DbDataRecord)dr.GetValue(0)).GetValue(1));
}
}
}
// All customers as CustomerName value through EntityClient provider
using (var cn = new EntityConnection(ef4TestEntities))
using (var cmd = new EntityCommand(allValueCustomerNames, cn))
{
cn.Open();
using (var dr = cmd.ExecuteReader(CommandBehavior.SequentialAccess))
{
while (dr.Read())
{
Console.WriteLine("{0} {1}", dr.GetValue(0), dr.GetValue(1));
}
}
}
// All customers as raw DbDataRecords through ObjectContext
using (var context = new EF4TestEntities())
{
var customerNames = context.CreateQuery <DbDataRecord>(allCustomerNames);
foreach (var c in customerNames)
{
Console.WriteLine(((CustomerName)c.GetValue(0)).FirstName);
}
}
// All customers as CustomerName through ObjectContext
using (var context = new EF4TestEntities())
{
var customerNames = context.CreateQuery <CustomerName>(allValueCustomerNames);
foreach (var c in customerNames)
{
Console.WriteLine("{0} {1}", c.FirstName, c.LastName);
}
}
// Michael as CustomerName through ObjectContext
using (var context = new EF4TestEntities())
{
var customerNames =
context.CreateQuery <CustomerName>(michaelValueCustomerNames,
new[] { new ObjectParameter("firstName", "Michael") });
foreach (var c in customerNames)
{
Console.WriteLine("{0} {1}", c.CustomerId, c.FirstName);
}
}
// All customers as CustomerName through LINQ
var all = from cn in new EF4TestEntities().CustomerNames
orderby cn.EmailAddress
select new { Id = cn.CustomerId, First = cn.FirstName, Last = cn.LastName };
foreach (var cn in all)
{
Console.WriteLine("{0} {1}", cn.Id, cn.First, cn.Last);
}
// Michael as CustomerName through LINQ
var michael = from cn in new EF4TestEntities().CustomerNames
where cn.FirstName == "Michael"
select cn;
Console.WriteLine((michael as ObjectQuery).ToTraceString());
foreach (var cn in michael)
{
Console.WriteLine("{0} {1}", cn.FirstName, cn.LastName);
}
}