In most cases, the layer of sweet kindness between entity objects and SQL writing is your DAL. The whole purpose of LINQ is to provide much more expressive designs with your DAL than was possible in the past.
LINQ BL , GetCustomersByLastName(string), DAL. , , - , - BL . , DAL BL. LINQ BL DAL. DAL ; , , . true .
LINQ DAL, LINQ?