What Are Content Types, Anyway?
One of the major new concepts in Windows SharePoint Services V3 is content types. They're a core concept that enables a lot of the functionality in both Windows SharePoint Services and Office SharePoint Server 2007, so they seemed like a logical choice to talk about.
A content type is a reusable collection of settings you want to apply to a certain category of content. Content types enable you to manage the metadata and behaviors of a document or item type in a centralized, reusable way. Basically, content types include the columns (or fields, if you prefer) you want to apply to a certain type of content, plus other optional settings such as a document template, and custom new, edit, and display forms to use.
You can think of a content type as a refinement and extension of a Windows SharePoint Services 2.0 list. The list schema defined a single group of data requirements for each item on that list. So in Windows SharePoint Services 2.0, the schema of an item was inextricably bound to its location.
With content types, you can define a schema for types of content, but that schema is no longer bound to a specific location. And to look at it in reverse, each SharePoint list is no longer limited to a single data schema to which the documents stored there must adhere. You can assign the same content type to multiple document libraries, and you can assign multiple content types to a given document library. Content types, in essence, let you:
· Store the exact same type of content in multiple locations
· Store multiple types of content in the same location
Site and List Content Types: Parents and Children
There are two different levels of content types I should mention: site content types, and list content types. Think of site content types as templates, and list content types as instances of those templates. You define site content types at the um, site level, hence the name. Since site content types aren't bound to a specific list, you can assign them to any list within the site you want. The site at which you define the site content type determines the scope of that content type.
List content types are more like instances, or single-serving content types. When you assign a site content type to a list, a copy of that content type is copied locally onto the list. That's a list content type. You can even tweak a list content type so that it's different from its site content type 'parent'. Also, you can create a content type directly on a list, but it's a one-off. You can't then assign that list content type to other sites or lists.
One other thing about site content types: you can base content types on other site content types. For example, Windows SharePoint Server comes with a built-in hierarchy of content types for basic SharePoint objects, such as Document, Task, Folder, etc. You can create your own site or list content types based on one of these site content types. Ultimately, all content types derive from the grandfather of them all, System.
Also, if you make changes to a site content type, Windows SharePoint Services includes a mechanism whereby you can 'push down', or propagate those changes out to the child content types (be they site or list content types). Doesn't work the other way, though; no pushing changes to child content types up the family tree.
E is for Extensible
You can see how content types were designed to encapsulate and modularize schema settings in Windows SharePoint Services V3. One very powerful aspects of this is that you can use content types to encapsulate whatever custom data you want to include in them. The content type schema includes a <XMLDocuments> node, which you can use to store nodes of any valid XML. As far as Windows SharePoint Services is concerned, the contents of the <XMLDocuments> node is a black box. Windows SharePoint Services makes no attempt to parse any of the XML documents you store there; it simply makes sure that they are included in any children content types, such as when you assign the content type to a list.
The <XMLDocuments> node was designed to be utilized by third-party solutions. Use it to store information pertinent to any special settings or behavior you want to specify for a certain type of content. Office SharePoint Server uses this mechanism to store information various features need, such as information policies and document information panels, among others. You can programmatically access a SharePoint item’s content type, and from there access the XML documents include in the content type.
Find Out More
And here’s a few places content types are utilized to facilitate Office SharePoint Server functionality: