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Microsoft SharePoint Metadata

by: Michael Mullin, Consultant, CRCP, MCAD

The last time we gathered I promised that I would discuss content management. But while pondering that subject it occurred to me that we should first discuss some other subjects. The first of these is metadata. Metadata is usually defined as “data about data”. I must admit the term always reminds me of an English Professor at OSU who once told me that Sociologists like to use big, obscure words so that people would think they were real scientists. Did he foresee Computer Science?

It is possible for data to be both metadata and data at the same time. As an example, the title of this article “Microsoft SharePoint Metadata” is metadata since it describes the data in this article and it is data since it is part of the article itself. But wait! In this case the metadata includes the word “metadata” itself so “metadata” has become both metadata and data. I am having too much fun with this, I shall proceed.

SharePoint contains a lot of lists. A Library Web Part is list of documents, a Tasks Web Part is a list of Tasks, and Photo Web Part is a list of photos. A list is just a table. Tables have rows and columns. In SharePoint, the user can add columns to these lists. On the menu bar above the library, tasks, photo, links, or other web part will be an item called “Settings”. (Depending on permissions assigned to users this menu selection can be hidden.) One of the items on the Settings Drop Down menu is “Create Column”. This menu choice will add a column to the list. These columns can be used to store information which describes the item in the list. In other words, the columns contain metadata.

Columns are easy to create, Select the Settings/Create Column menu item and SharePoint will present you with a web page for creating the column.

Assign a column name, choose a data type and you have a new column. If you specify that a column is required, then a user will not be able to add an item to the list which contains the column without providing a value for the column. Actually there are a lot more settings to a column than these. The available settings vary depending on the data type that you chose for the column. For a column with a Date and Time data type, you can choose between saving the “Date Only” and “Date & Time”. You can usually specify a default value for a column too. Although the new column is added to your list, it does not have to be displayed.  When creating a view of the list, the new column will appear in the list of columns available and can be turned on or off.

The column created above is part of a particular list. It is also possible to create a site column. Site columns allow you to create a column once and use it in many places. For instance, you might decide that you always want a column on every list to contain the name of the person who created the list item. This could be accomplished by creating a new column for every list on the site using the same procedure described above. However, this is tedious and prone to error. To create a site column, you must have access to the “Site Actions” menu. Clicking on the Site Actions/Site Settings menu item will display the Site Settings, which is a page with links to a lot of other pages, one being the Site Columns Gallery.

Creating a column from the Site Column Gallery page is the same as described above. The only difference is the column is not added to any lists. Site columns can be added to any list on a site or any of the site’s sub-sites (aka child sites). If we want to have a column for “Created By” used in every list, we can create as a site column for the topmost site of the site collection. When we create a new list any where in the site collection this column will be available to add to the list.

Site columns also have another very interesting characteristic. Let us assume the “Created By” column has been created and assigned to many lists throughout the site. Furthermore, when we created the column, we forgot to specify the column as required, which would force the user to populate the column with data whenever a new item was added to the list. We can go back to the site column gallery and edit the column definition. When we do this we will be presented with a choice at the bottom of the Change Site Column Page for updating the list.

If we choose yes, our modifications will be propagated to all existing columns which are based on our original definition. This helps maintain a uniform behavior throughout our sites.

It is easy to see that adding columns to all our lists can be very useful. Just remember that when referring to columns, do not call them columns. Call then metadata. No one will understand you, but they will think you are very smart!

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