The following diagram shows the SharePoint Foundation site architecture in relation to the collections and objects of the Microsoft.SharePoint namespace.

- Each SPSiteobject, despite its singular name, represents a set of logically related SPWeb objects (see below). Such a set is commonly called a "site collection," but SPSite is not a standard Microsoft .NET collection class, in contrast to SPWebCollection. Rather, it has members that can be used to manage the site collection. The AllWebs property provides access to theSPWebCollection object that represents the collection of all Web sites within the site collection, including the top-level site. The SPSite.OpenWebmethod of the SPSite class returns a specific Web site.
- Each site collection includes any number of SPWeb objects, and each object has members that can be used to manage a site, including its template and theme, as well as to access files and folders on the site. The Webs property returns an SPWebCollection object that represents all the subsites of a specified site, and the Lists property returns an SPListCollection object that represents all the lists in the site.
- Each SPList object has members that are used to manage the list or access items in the list. The GetItems method can be used to perform queries that return specific items. The Fields property returns an SPFieldCollection object that represents all the fields, or columns, in the list, and the Items property returns an SPListItemCollection object that represents all the items, or rows, in the list.