Guide to Entity Framework with

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 19 
]
cmd.Parameters.AddWithValue("FirstName", 
"Joydip");
cmd.Parameters.AddWithValue("LastName", 
"Kanjilal");
cmd.Parameters.AddWithValue("Address", 
"Hyderabad");
cmd.Parameters.AddWithValue("DepartmentID", 
4);
cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
To query data from the EDM, you have three choices—Entity 
SQL, LINQ to Entities, and Object Services.
Avoiding complex joins
You can use Entity SQL
to avoid complex joins as you will typically be querying 
against a conceptual model of the data. As an example, if we want to display 
employee names and the department names in which they work, we would have to 
join the information of the 
Employee
and the 
Department
tables and then filter the 
unwanted columns to retrieve only the information that is required. Such traversals 
become a nightmare as you add additional tables and therefore require more 
complex joins.
When you implement your Object Model using object-oriented programming 
languages, you expose the object's relationships to other objects of its kind using 
properties. This is in contrast to the approach we just discussed. Hence, designing 
an Object Model using this approach is cumbersome. This is exactly where Entity 
Framework fits in; it represents the conceptual and logical model of data while 
using grammar that is common to both.
Here is a code snippet that explains how you can use Entity SQL to avoid complex 
joins in your application's code. The following T-SQL query can be used to retrieve 
employee data split across three tables, namely, 
Employee
, 
Department
, and 
Salary
:
Select Employee.FirstName, Employee.LastName,
Department.DepartmentName, Salary.Basic

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Introducing the ADO.NET Entity Framework