All three types of searches would still be possible according to the parameters used, and the custom search would use XML schema instead of a simplified structure representation.

A full document search would look like:

<search>

  <responseStructrure ns="http://www.tdwg.org/schemas/abcd/1.0"></responseStructrure>

</search>

Implying that the responseStructure schema is a conceptual schema accepted by the provider.

A partial document search would look like:

<search>

   <responseStructrure ns="http://www.tdwg.org/schemas/abcd/1.0"></responseStructrure>

  <concepts>

    <concept path="/datasets/dataset/units/unit/identification"/>

  </concepts>

</search>

Also implying that the responseStructure schema is a conceptual schema accepted by the provider. In this case all mandatory elements from the response schema would be returned, including the additional concepts specified.

The custom search would also use an XML schema to specify the response structure, but now this schema would not be a conceptual schema accepted by the provider:

<search>

  <responseStructrure ns="http://www.mydomain.org/myschema/1.0">http://www.mydomain.org/myschema/1.0/myschema.xsd</responseStructrure>

  <mapping xmlns:abcd="http://www.tdwg.org/schemas/abcd/1.0">

    <concept>
     <from path="Taxon/@FullName" SearchRequestProposalTwo>
     <to path="abcd:/datasets/dataset/units/unit/identification/scientificname" SearchRequestProposalTwo>
    </concept>
    <concept>
     <from path="Taxon/@HigherTaxon" SearchRequestProposalTwo>
     <to path="abcd:/datasets/dataset/units/unit/highertaxon" SearchRequestProposalTwo>
    </concept>
    <concept>
     <from path="Taxon/Coordinates/@lat" SearchRequestProposalTwo>
     <to path="abcd:/datasets/dataset/units/unit/latitude" SearchRequestProposalTwo>
    </concept>
    <concept>
     <from path="Taxon/Coordinates/@long" SearchRequestProposalTwo>
     <to path="abcd:/datasets/dataset/units/unit/longitude" SearchRequestProposalTwo>
    </concept>

  </mapping>

</search>

However it would give the provider the necessary mappings to produce the results.

A custom search could also accept a list of concepts (as the partial search).

Providers could cache the mappings to speed up responses (should we also include a "useCache" attribute?)

Note: The recordDefinition elements would still be necessary here!

The custom schema above could look like:

<element name="Taxon" maxOccurs="unbounded">
  <complexType>
    <attribute name="FullName" type="xsd:string" use="required"/>
    <attribute name="HigherTaxon" type="xsd:string"/>
    <sequence>
      <element name="Coordinates" maxOccurs="unbounded">
        <complexType>
          <sequence>
            <element name="lat" type="xsd:string" use="required" SearchRequestProposalTwo>
            <element name="long" type="xsd:string" use="required" SearchRequestProposalTwo>
          </sequence>
        </complexType>
    </sequence>
  </complexType>
</element>