-sqlddt
template: pers?clnt=<name|pass>&com=sqlddt&whr=<where_pattern>
          Order of query params is not important.
pattern : * | <SQL part following WHERE>. The '*' means all.
          A special syntax must be used: ':' for = and '|' for <space>.
          This is because spaces and '=' are replaced in WWW requests.
          Note that string values must be enclosed in single quotes.
descript: returns part of the table 'decay_data' as specified
          by the condition in the 'whr' query parameter. If no
          row in DB satisfies the conditions, the result will
          not have any 'row' elements (200 OK will still be returned).
example : pers?clnt=name|pass&com=sqlddt&whr=dd_user:'us101'|and|dd_feature:'advert.banner6'|order|by|dd_timestamp|desc
          pers?clnt=name|pass&com=sqlddt&whr=*
          pers?clnt=name|pass&com=sqlddt&whr=dd_feature:'page3.link8'|and|dd_timestamp>1005854664569
returns : 200 OK, 401 (fail, request error), 501 (fail, server error)
200 OK  : in this case the response body is as follows
          <?xml version="1.0"?>
          <?xml-stylesheet type="text/xsl" href="/resp_xsl/decay_data.xsl"?>
          <result>
              <row><usr>user</usr><ftr>feature</ftr><timestamp>timestamp</timestamp></row>
              ...
          </result>
comments: the reference to the xsl file allows to view results
          in a web browser. In case the response body is handled
          directly by an application and not by a browser, this
          reference to xsl can be ignored.