Metadata navigation overview (SharePoint Server 2010)
Applies to: SharePoint Server 2010
Topic Last Modified: 2011-09-28
The Metadata Navigation and Filtering Feature in Microsoft SharePoint Server 2010 can help users filter and find content.
This article contains information to help solution planners and designers understand how the Metadata Navigation and Filtering Feature in Microsoft SharePoint Server 2010 can be used as part of a comprehensive document management solution.
In this article:
Metadata Navigation and Filtering is a new feature in SharePoint Server 2010 that enables users to filter and find content in document libraries by using metadata. The Metadata Navigation and Filtering Feature includes the following:
A simple user interface Metadata navigation builds upon the SharePoint Tree view hierarchy control and combines it with a new Key Filters control providing users a powerful tool in finding content based on metadata.
List owner controls By configuring metadata navigation settings, list owners can promote fields on a list as key navigation fields. Users viewing those lists can then further filter the current list view to show only items with the desired values in those fields.
Automatic indexing This optional process can create list indices automatically depending on the fields promoted as navigational fields for the list. Automatic indexing can improve query results and improve performance.
For information about how to enable the Metadata Navigation and Filtering Feature, see "Enable Metadata Navigation and Filtering" in the article Configure metadata navigation for a list or library (http://go.microsoft.com/fwlink/p/?LinkId=229369).
Metadata navigation builds on list view navigation features already in SharePoint. List views without metadata navigation configured provide a simple hierarchical view and work well when searching for content through its physical structure, for example sites, libraries, and folders. However, those list views are blocked when trying to navigate through many items, or by the list view threshold when browsing folders that contain more than five thousand items.
|By default, the list view threshold is 5000 items. Administrators can change the list view threshold by using Windows PowerShell.|
Metadata navigation expands the capabilities of list views and combines it with a Key Filters control making it easier for users to find content by filtering a view of documents to a subset based on one or more navigation filters.
Metadata navigation includes the following user controls:
Navigation hierarchies Use and expand the capabilities of list views to navigate hierarchies of folders, content types, choice fields, or managed metadata term sets. This allows users to use list views to filter on a metadata hierarchy just like navigating folders.
When selecting an item in a hierarchy for a managed metadata column, all items will be shown that are tagged with the specified term or any of its descendant terms for the field associated with that hierarchy. Users can then select the item again to filter only on that particular term and not include the descendant child terms.
Navigation hierarchies work together with filters specified in the list view definition and filters specified in the columns in the list view Web Part.
Key Filters This control appears below the site hierarchy control and can consist of several fields such as date, choice, content type, single and multi-value fields, currency, yes / no, and user fields. Any number of key filters can be applied in combination with a selected navigation hierarchy.
Key filters can be specified for a much larger range of column types and consist of a blank field that matches the kind of column it represents. Users can then type text into the field to filter on that column. For example, you can add the modified by column as a key filter and then type a user display name or username alias and resolve to get results where modified by matches the user entered. Any number of key filters can be used at the same time and they can also be used in combination with a navigation hierarchy.
Managed metadata key filter fields enable entering multiple terms by typing and selecting from the suggestions displayed. A specially handled managed metadata field that is named All Tags can also be used, which matches the input terms against field values for an item in any of the managed metadata fields in the list schema. If the user is in the root folder of the list then applying key filters will query over all of the items from any of the folders in the list.
Once the Metadata Navigation and Filtering Feature is enabled for a site, list or library owners can configure settings on the Metadata Navigation Settings page available from the list or Document Library Settings page. Owners can specify navigation hierarchy and key filter fields and specify whether columns are automatically indexed.
On the Metadata Navigation Settings page for a list or library, with the Configure automatic column indexing for this list setting, list owners can specify whether indices are automatically created on the list to match selected navigation hierarchy and key filter fields. If this setting is enabled (default), when the metadata navigation settings page is saved, the following occurs:
Single column indices will be created on all supported navigation hierarchy fields.
Single column indices will be created on all supported key filter fields, except for the Content Type field and Choice fields
Compound indices will be created on all supported combinations of navigation hierarchies and key filters.
When indices are created automatically, queries are allowed for lists that have more items than the list view threshold. In some cases, you may have to disable this setting and configure custom indices. For example, if a combination of single column and compound indices exceeds 20, Automatic Indexing must be disabled.
When the Metadata Navigation and Filtering Feature is enabled for a site, built-in optimization will select the best index to work every time that a list view is loaded. Each time that a user loads a list view, refreshes a list view by applying a new filter, clearing a filter, or by applying a sort on a field, query optimization determines the best way in which to query the database without view throttling.
If metadata navigation determines that the current user request cannot be expressed as an indexed query that is selective, it will construct and perform a fallback query. A fallback query is a modified version of the original user query that queries against only a part of the list instead of the complete list. Fallback queries are intended to show the user a partial set of results that can be useful, even when the original query could not be run because of list view throttling. In addition, fallback queries can serve as a warning to list owners that the data distribution in the list is skewed and certain queries that users are running cannot return a full set of results, which means that users may be blocked from accessing content that they need. Fallback queries occasionally will return 0 results if no items in the part of the list scanned by the query contain results that match the original user query.
Since the results of a fallback query are only a partial set of the items that the user is requesting, the user is prompted via an on-screen message that only a partial set of results is being shown and that the user must apply additional filters in order to view a complete set. Every time that a user specifies an additional filter, this is another opportunity for the query engine to find a selective filter/index combination that does not exceed the list view threshold that result in a throttling exception.