how can I appoint NULL value to an integer data type?

A nullable int-compatible type: System.Data.SqlTypes.SqlInt32

There are two types of symbols in C#. There are reference types and value types. NULL can only be applied to reference types. Reference types are objects. Value types are primitives and structs. An int is a primitive. A value type must only contain a value. NULL is itself a reference with special meaning (a reference to absolute address 0, usually). To assign a reference to a symbol, the symbol must be a reference type.

WTF....a null value to an int? Then how can it even be an int if its null? it could be a string at that point. Anyways, can't you just do "int x;" and leave it as that?

why would you want to appoint a null to a integer? NULL is practically evaluated to 0 anyways.