Guide to Entity Framework with

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EntityClient, the gateway to entity-level queries, is the Entity Framework's 
counterpart of ADO.NET's SQL client or Oracle client that uses Entity SQL or E-SQL 
to query the conceptual model. You create a connection using the entity connection, 
execute commands through entity commands, and retrieve the result sets as entity 
data readers. The MSDN states:
 "The EntityClient provider is a data provider used by Entity Framework 
applications to access data described in a conceptual model."
Entity SQL
Entity SQL is a data store independent derivative of T-SQL that supports entity 
inheritance and 
relationships. You can use it to query data using the conceptual 
schema. You can even build your own dynamic queries. These E-SQL queries are 
internally translated to data store dependent SQL queries. This translation of the 
E-SQL queries to their data store-specific query language like T-SQL, (it doesn't 
need to be only T-SQL, however, it is the supported one), is handled by the Entity 
Framework. Entity SQL or E-SQL may not be as strongly typed as LINQ is, but you 
have the flexibility of executing dynamic queries using it, much like T-SQL.
Strongly typed data access is one of the most striking features of LINQ. 
LINQ queries are checked at compile time. This is unlike SQL queries, 
which are only detected at runtime.
But, why do you need Entity SQL when you have LINQ to Entities to query data 
through
your EDM? You can, using Entity SQL, compose queries that are difficult to 
determine until the time the query is executed. On a different note, Entity SQL is a 
full text-based query language that you can use in much the same way as you use
the ADO.NET data providers.
Here is an example that shows how you can use Entity SQL to insert data into
your applications:
using (EntityConnection conn = new 
EntityConnection("Name=PayrollEntities"))
{
try
{
conn.Open();
EntityCommand cmd = conn.CreateCommand();
cmd.CommandText = 
"PayrollEntities.AddNewEmployee";
cmd.CommandType = CommandType.StoredProcedure;

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Chapter 1