Sitecore abstracts its data access using a data provider model. In brief, a data provider is like an interface that – if implemented fully – allows Sitecore to “plug in” to any database or other content repository. Due to the complexity of implementing a complete data provider, it is a strongly discouraged practice. There are almost always preferable alternatives which vary depending on whether your primary requirement centers on presentation, data entry or both.
We discuss the topic briefly here as developers may find occasion to implement simple, read-only data providers and because some Sitecore modules (such as the Sitecore Sharepoint Module) may leverage this architecture. In any case, data providers are rendered in the content tree and warrant mention here for that reason alone. Considerations around how to design a data provider, i.e. represent relational data hierarchically, is considered outside of scope for this document.
Data from data providers can be viewed by switching databases using the database chooser located in the lower right-hand corner of the Sitecore taskbar. Clicking on the database icon allows developers to view any of the seven standard Sitecore databases as well as any additional data providers that have been defined for the Sitecore instance. Opening the content editor will represent the data from the data provider in a familiar hierarchical view.
To represent this data within the master database, developers typically create proxy items. See the discussion above on proxy items and reference items for more information.
Another approach to integrating external data into Sitecore is relying on legacy applications that may have presentation components. Often, it is desirable for these components to be served from the same web root. In other words, /Products.aspx and /Profiles.aspx may co-exist under the same web root; however, Products.aspx is served by Sitecore while Profiles.aspx is handled by a legacy application. The standard solution for this requirement is to configure the IgnoreUrlPrefixes setting in the web.config. IgnoreUrlPrefixes allows developers to indicate that requests for certain files or directories should be ignored by Sitecore’s processors.
While this doesn’t explicitly affect the design of the content tree, it implicitly does. Any path specified in IgnoreUrlPrefixes will never be a valid Sitecore path (unless the value for the setting is changed); in other words, the system will never try to resolve the item to an actual content item. Content editors will need to be aware of these excluded paths or file names to ensure they do not create content items with identical names.