Use the
Ne
parameter to expose refinement dimension values.
Refinement dimension values are only returned with a valid
navigation query. Therefore the
N
(Navigation) parameter is required for any request
that will render navigation refinements. The other parameter required in most
cases to render navigation refinements is the
Ne
(Exposed Refinements) parameter.
The
Ne
parameter specifies which dimension, out of all valid
dimensions returned with a Navigation query, should return actual refinement
dimension values. Note that only the top-level refinement dimension values are
returned. If a dimension value is a parent, you can also use the
Ne
parameter with that dimension value and return its
child dimension values (again, only the top-level child dimension values are
returned).
Keep in mind that the
Ne
parameter is an optional query parameter. The default
query (where
Ne
is not used) is intended to improve computational
performance of the MDEX Engine, as well as reduce the resulting object and
final rendered page sizes.
For example, in a simple dataset, the query:
N=0
will return three dimensions (Wine Type, Year, and Score) but no refinement dimension values. This is faster for the MDEX Engine to compute, and returns only three root dimension values.
However, the query:
N=0&Ne=6
(where 6 is the root dimension value ID for the Wine Type dimension) will return all three dimensions, as well as the top-level refinement dimension values for the Wine Type dimension (such as Red, White, and Other). This is slightly more expensive for the MDEX Engine to compute, and returns the three root dimension values (Wine Type, Year, and Score) as well as the top-level refinement dimension values for Wine Type, but is necessary for selecting a valid refinement.
A more advanced query option does not require the
Ne
parameter and returns all the top-level dimension
value refinements for all dimensions (instead of a single dimension). This
option involves the use of the
ENEQuery.setNavAllRefinements()
method (Java) or the
ENEQuery.NavAllRefinements
property (.NET). If an
application sets this call to true, the query:
N=0
will return three dimensions (Wine Type, Year, and Score) as well as all valid top-level refinement dimension values for each of these dimensions (Red, White, Other for Wine Type; 1999, 2001, 2003 for Year; and 70-80, 80-90, 90-100 for Score).
This is the equivalent of the query:
N=0&Ne=6+2+9
(where 6, 2, and 9 are the root dimension value IDs for the three dimensions). This is the most expensive type of query for the MDEX Engine to compute, and returns three root dimension values as well as the nine top-level refinement dimension values, creating a larger network and page size strain. This method, however, is effective for creating custom navigation solutions that require all possible refinement dimension values to be displayed at all times.