e938ed2d_SharePoint_Server__2007__2010___SharePoint_Farm_Solution
[0] Coding Options [Sandboxed Solution] In Sandbox Solutions the Server side object model can be used but it is restrictive in nature. The solution can only access content from the site collection in which it was deployed. [Apps for SharePoint] Business logic in an app for SharePoint can access SharePoint data through one of the several client APIs included in SharePoint 2013 such as .NET Framework client object model, Silverlight or JavaScript Client Object model code, REST endpoints & Mobile client object model. The server object model can not be used in the Apps for SharePoint. [SharePoint Farm Solution] 
In Farm Solutions the Server side object model can be used. The data acces is unrestricted.
A Point For Sharing On SharePoint Server (2007, 2010)
SharePoint Farm Solution