If you need to re-create the entire CustomerModel.edmx make sure to remove the 
following line from the business layer App.Config before re-creating since you will need to re-use the name CustomerSingleViewEntities.
Create the model with name "CustomerModel" and it will auto-generate the entities name.

<add name="CustomerSingleViewEntities" connectionString="metadata=res://*/CustomerModel.csdl|res://*/CustomerModel.ssdl|res://*/CustomerModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=MDMKDCSQL89;initial catalog=CustomerSingleView;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework&quot;" providerName="System.Data.EntityClient" />