Understanding the Administrative Object Model of Windows SharePoint Services 3.0
The SharePoint .NET object model. Just to review. SPWebApplication is the Web Application sitting at either a host heater or a port. It is an IIS web site. SPContentDatabase is the SQL Server Database assigned to a Web Application. Web Applicaitons contain one or more sites SPSite, and SPSite contains one or more SPWeb which are pages.
Some characteristics of the SPWeb class are as follows:
An SPWeb object can be a child of another SPWeb object or of an SPSite object. If it is the child of an SPSite object, it is the top-level Web site in its site collection.
An SPWeb object has a Webs property that returns a collection of other SPWeb objects; specifically, the immediate child subsites under it.
The class has a very rich set of members for programmatic administration and customization of the Web site.
A hierarchy of Web sites always has exactly one top-level Web site. This site is the child of an SPSite object. You can learn more about the top-level Web site in the section Windows SharePoint Services Site Collections later in this article.