RE: [search-ws] Scan operation

["LeVan,Ralph" <levan@oclc.org>]

> http://myserver.com/sru?operation=scan&version=1.2&scanClause=dc.title
= 
> frog

That would provide you with a list of single terms from the dc.title
index in the neighborhood of the term "frog".

And I can see that there are all sorts of assumptions in that statement.
When an index is scannable (and there is no requirement that any be
scannable), then the terms in the index are provided in a sorted order.
Essentially, a dictionary of terms is produced.  The scan operation
provides a window into that sorted list of terms, in the neighborhood of
a provided seed term.  If no seed term is provided, then the scan takes
place at the top of the index.  (An empty term is assumed and it sorts
to the top of the index.)

The "neighborhood" is determined by other optional parameters.  You can
specify where the seed term should appear in the list of returned terms
(if it appears) and how many terms you want returned.  When omitted, the
server may provide default values.  On my servers, the default is to
return 10 terms and to return the seed term (or closest term to the
seed) in position 5.  That gets you a list of 10 terms with yours in the
middle.

To continue browsing forward, the client would return to the server the
last term from the previous scan response and indicate that it should be
the first term on the next response.  Similarly, browsing up in the
index is done by returning the first term and indicating that you'd like
it to be the last term on the next response.

Hope this helps!

Ralph