You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create an application.
The application contains the following code segment. (Line numbers are included for reference only.)
01 class DataAccessLayer
02 {
03 private static string connString;
04
05 ...
06 public static DataTable GetDataTable(string command){
07
08 ...
09 }
10 }
You need to define the connection life cycle of the DataAccessLayer class. You also need to ensure that
the application uses the minimum number of connections to the database.
What should you do?

• A. Insert the following code segment at line 04. private SqlConnection conn = new SqlConnection(connString); public void Open(){
  conn.Open();
  }
  public void Close(){
  conn.Close();
  }
• B. Replace line 01 with the following code segment.
  class DataAccessLayer : IDisposable
  Insert the following code segment to line 04.
  private SqlConnection conn = new SqlConnection(connString);
  public void Open(){
  conn.Open();
  }
  public void Dispose(){
  conn.Close();
  }
• C. Insert the following code segment at line 07. using (SqlConnection conn = new SqlConnection(connString)){
  conn.Open();
  }
• D. Insert the following code segment at line 04. private static SqlConnection conn = new SqlConnection(connString); public static void Open(){
  conn.Open();
  }
  public static void Close(){
  conn.Close();
  }

You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create an application. The application uses the ADO.NET Entity Framework to model entities. You need to create a database from your model. What should you do?

• A. Use the Update Model Wizard in Visual Studio.
• B. Use the Generate Database Wizard in Visual Studio. Run the resulting script against a Microsoft SQL Server database.
• C. Run the edmgen.exe tool in FullGeneration mode.
• D. Run the edmgen.exe tool in FromSSDLGeneration mode.

You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create an application. The
application uses the ADO.NET Entity Framework to model entities. The application allows users to make
changes to entities while disconnected from the central data store.
You need to ensure that when the user connects to the central data store and retrieves new data, the
application meets the following requirements:
*Changes made to the local data store in disconnected mode are preserved.
*Entities that have already been loaded into the local data store, but have not been modified by the user,
are updated with the latest data.
What should you do?

• A. Call the query's Execute method by using the MergeOptions.AppendOnly option.
• B. Call the query's Execute method by using the MergeOptions.OverwriteChanges option.
• C. Call the Refresh method of ObjectContext by using the RefreshMode.StoreWins option.
• D. Call the Refresh method of ObjectContext by using the RefreshMode.ClientWins method.

You use Microsoft Visual Studio 2010 and Microsoft .NET Framework 4 to create an application. The application uses the ADO.NET Entity Framework to manage customer and related order records. You add a new order for an existing customer. You need to associate the Order entity with the Customer entity. What should you do?

• A. Call the Add method on the EntityCollection of the Order entity.
• B. Set the Value property of the EntityReference of the Order entity.
• C. Use the AddObject method of the ObjectContext to add both Order and Customer entities.
• D. Use the Attach method of the ObjectContext to add both Order and Customer entities.