LINQ query with a WHERE clause with multiple conditions

Question

I use EntityFramework with POCOs.
Suppose I have POCOs defined like this (simplified):

class Class1
{
    public int ID;
    public int SomeNumber;
}

class          


        

Answer 1

IMHO you should be OK with just this:

Database DB = new Database(); 
var result = DB.SomeClass.Where(x =>
                            Number == x.Class1.SomeNumber ||
                            Number == x.Class2.SomeNumber ||
                            Number == x.Class3.SomeNumber)
                         .ToList();

Your query loads all data and after that you evaluate condition in .NET = you must test null value prior to accessing SomeNumber but that is not needed if you evaluate SomeNumber in SQL through Linq-to-entities. Linq-to-entities should perform automatic null coalescing.