Guided Navigation is the presentation of valid follow-on refinement queries to the user.
You can think of Guided Navigation as the elimination of invalid refinement queries or dead ends. To understand how the MDEX Engine accomplishes Guided Navigation, we’ll look at the refinement information that the MDEX Engine returns in response to a query.
Note
Unless otherwise stated, everything in this section pertains to both navigation queries and record search queries (a type of keyword search query described in the "Record search" topic).
The refinement information that is returned for a query is specific to the record set that is returned for the query. For example, if a returned record set contains only red wines, refinements associated with white or sparkling wines are not returned. It is the record data that is returned for a query, therefore, that drives which refinements are also returned with the query.
A dimension is a tree of dimension values. The tree structure makes it easy to imagine a specific location within a dimension. It also makes it easier to see the intersections among dimension values. However, the tagging of records with dimension values happens at the record level. Thus, in the following illustration the data in the column on the right more accurately represents the data in the MDEX Engine than the trees structures.
Every query returns a set of records that are tagged with dimension values, much like the physical representation above. From this representation, the MDEX Engine can quickly determine which dimension values are tagged to the returned records and which are not. This dimension value tagging determines what follow-on query information is returned along with the set of records:
Any dimension value that is tagged to at least one record in the returned record set is considered a valid refinement (because querying the dimension value would return at least one record). The follow-on refinement queries for these dimension values are returned in the query results.
Dimension values that are not tagged to any records in the returned record set are considered invalid. No follow-on query information is returned for these dimension values.
To understand this concept better, remember that querying a dimension value returns the set of records that have been tagged with that dimension value. If none of the records in a record set have been tagged with a particular dimension value, then querying that dimension value would produce no results. This makes the dimension value an invalid refinement option.
When data is tagged with dimension values and follow-on queries are refined as described above, the MDEX Engine can dynamically build navigation paths among the Endeca records in a data set. Users can navigate along any path supported by the current record set, and the set of paths is updated as the record set changes. These features are the essence of Guided Navigation.
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