Sqlmap: automatic SQL injection tool. LINQ to SQL N-Tier with Web Services. The client or presentation tier must have type definitions for the classes that it will be receiving from the middle tier.
Those types may be the entity classes themselves, or special classes that wrap only certain fields from the entity classes for remoting. In any case, LINQ to SQL is completely unconcerned about how the presentation tier acquires those type definitions. N-Tier and Remote Applications with LINQ to SQL. You can create n-tier or multitier applications that use LINQ to SQL.
Typically, the LINQ to SQL data context, entity classes, and query construction logic are located on the middle tier as the data access layer (DAL). Business logic and any non-persistent data can be implemented completely in partial classes and methods of entities and the data context, or it can be implemented in separate classes. Four ways to work with hierarchical data.