---+ FourthProposal

---+++++ General strategy
Based on the SecondProposal and the BerlinMeetingResults develop a new proposal to accomodate all of the suggested changes. Still indicating open or problematic issues.

---+++++ Files

   * *old protocol schema based on the BerlinMeetingResults* :
   http://www.bgbm.org/biodivinf/Schema/protocol4.xsd


---+++++ Ideas included not part of the BerlinMeetingResults
   * FilterEncoding
   * allow comparative operators to compare any 2 expressions, which can be made of literals (values) or concepts. This would allow to compare 2 concepts also instead of the current restriction to compare a concept with a literal only.
   * Remove the CustomSearch from the protocol. See the SearchProposalTwo for details of the SearchRequest.
   * The RecordDefinition is removed from the request and is thought of being inherent to each ConceptualSchema. A list of RecordDefinitions can now be retrieved by the CapabilitiesRequest (see CapabilitiesProposalFour).
   * capabilities response definition seperated for providers and datasources (see CapabilitiesProposalFour)
      * a provider can return allowed request types and a flag to indicate whether he accepts requests for multiple datasources
   * response content element not repeatable anymore, because merging of responses will not take place. Multiple sets of metadata and acompanying records are now grouped by a repeatable recordset element.
      * see SearchResponseTopStructure
   * footer included to hold paging information that was called totals before. It needs to count records for the whole content and not for recordsets only as proposed.
   * add element "responses" for providers or portals to wrap single responses. Provider access points should always use this for responding even a single response document from one datasource.
   * changed header information to fit the HeaderProposalTwo. Mainly assigning a destination only to one accesspoint while allowing to address several datasources.