Metadata Property Mappings

In order for me to make full use the FullTextSqlQuery SharePoint object which I spoke about in my previous blog here I needed to understand how metadata property mapping worked. This is my "lamens term" explanation: There are "Crawled Properties" which as a SQL developer you could think of as an indexed field. Then you get a "Managed Property" which you can map to multiple "Crawled Properties". The "Managed Property" is the field that will be available to use. You could think of this property as an interface to your indexed field(s).

So hopefully that doesn't make things more complicated, moving forward this is how you would go about creating Metadata Property Mapping:

To navigate to the Property Mapping Page go to Shared Services Provider. On the home page click on the "Search settings" option under "Search". The navigation menu should have changed now. Click on the "Metadata properties" item in the quick launch menu under "Queries and Results". On this screen you can see all the managed properties and their crawled property mappings. From this page you are able to see all meta data properties. 

If you navigate to the "Title" propery and click on it you will see the following screen:

Let me explain what all these properties mean:

A. The type of information in this property. The available types are (Text, Integer, Decimal, Date and Time, Yes/No). Note that you can only link crawled properties that are the same type as your managed property.

B. The number of items found with this property. This is a very useful indication of whether your managed property will actually return any results. If this value is 0 is means one of two things.
1. Your mapped crawled properties do not contain any values
2. You haven't run a crawl yet. After you have created a managed property always run a crawl in order for SharePoint to index it.

C. Option "Include values from all crawled properties mapped" means that all mapped crawled properties will be returned in a deliminated fashion.
Option "Include values from a single crawled property based on the order specified" means that it will only return the first value that is not null depending on their order in the list box.

D. Crawled properties mapping to this managed property.
On the title example you will see that the first mapped property is "Mail:5(Text)". The keyword "Mail:" means that this crawled property will be retrieved out of a mail object. This full name is not very descriptive to the user but you can just google a field or test it out to find out what value it contains.

If you click on the "Add Mapping" Button you will be able to search for your desired property. If you are looking for a column inside a list or library you will find them under the "SharePoint" category. All custom column's crawled property names will begin with "ows_" and spaces will be converted to "_x0020_". Note: if you cannot find the property you are looking for check whether they are of the same type as your managed property. This has got me before ;)

E. Allow this property to be used in scopes.
This boolean value can be misleading in it's description. If this checkbox is selected it means that you will be able to create a rule in your scope that can use this property. If this property is unchecked you can still use scopes in conjunction with this field in your searches.

So one last thing to remember is ALWAYS RUN A CRAWL after any updates!!!