From an end user perspective it looks like there is only one field type that creates only a single taxonomy field in sharepoint; but this is not the whole story behind managed metadata fields. If a managed metadata field will be created SharePoint creates two fields instead. For this post I create a field called “TaxTest” which creates the field itself and a field “TaxTest_0”. I will use this field name for reference.
Let’s take a closer look on both fields that was created
- “TaxTest” Field is type of “TaxonomyFieldType”
- “TaxTest_0” field is type of “Multiple lines of text”
The TaxTest field is basically a lookup field. The target to look up is a hidden list in every site collection called TaxonomyHiddenList. This list only exists once per site collection and stores ever Managed Metadata term that ever was used in your site collection. The list cannot be found in SharePoint because it is a hidden list but can be located using the following URL pattern:
http://<yourserver>/<sitecollection root>/Lists/TaxonomyHiddenList or root site collection.
Field values stored in this field has also the same pattern as lookup fields and look like this: “1;#Test Term”
The “TaxTest_0” field will only store key/value pairs which looks like this:
TestTerm|15017394-438b-4c1d-b710-454c7055cc7
<Term value from Taxonomy Store>|<Term Guid from Taxonomy Store>
That’s all for now from these fields I will continue later on with this.[Read more]