Entity Framework to learn the primary chapter 6--entityclient

The System.Data.EntityClient namespace is a. NET Framework Data Provider for the Entity Framework. The EntityClient provider interacts with the Entity Data Model using storage-specific ado.net data provider classes and mapping meta data. EntityClient first converts an action performed on a conceptual entity to an operation performed on a physical data source. The result set returned by the physical data source is then converted to a conceptual entity.

The classes under EntityClient have several of the following:

L EntityConnection

L EntityCommand

L Entityconnectionstringbuilder

L Entityparameter

L EntityDataReader

L Entityparametercollection

L Entityproviderfactory

L Entitytransaction

From the names of the classes, we know what their role is. Here, it is no longer one by one explained. Learn them directly from the instance code.

L EntityConnection:

Instance Code 1:

string con = "name = NorthwindEntities";

using (EntityConnection econn = new EntityConnection(con))

{

string esql　= "Select VALUE c from NorthwindEntities.Customers as c where c.CustomerID='ALFKI'";

econn.Open();

EntityCommand ecmd = new EntityCommand(esql　, econn);

EntityDataReader ereader = ecmd.ExecuteReader(CommandBehavior.SequentialAccess);

if (ereader.Read())

{

Console.WriteLine(ereader["CustomerID"]);

}

Console.WriteLine(ecmd.ToTraceString());

}