correct so_Soil.xml

<?xml version="1.0" encoding="UTF-8"?>
<as:AppSchemaDataAccess xmlns:as="http://www.geotools.org/app-schema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.geotools.org/app-schema AppSchemaDataAccess.xsd">
<namespaces>
        <Namespace><prefix>gml</prefix><uri>http://www.opengis.net/gml/3.2</uri></Namespace>
        <Namespace><prefix>om</prefix><uri>http://www.opengis.net/om/2.0</uri></Namespace>
        <Namespace><prefix>sam</prefix><uri>http://www.opengis.net/sampling/2.0</uri></Namespace>
        <Namespace><prefix>sams</prefix><uri>http://www.opengis.net/samplingSpatial/2.0</uri></Namespace>
        <Namespace><prefix>xlink</prefix><uri>http://www.w3.org/1999/xlink</uri></Namespace>
        <Namespace><prefix>xsi</prefix><uri>http://www.w3.org/2001/XMLSchema-instance</uri></Namespace>
        <Namespace><prefix>soil</prefix><uri>http://www.opengis.net/soil-data-ie/0.1</uri></Namespace>
</namespaces>

    <sourceDataStores>
        <DataStore>
            <id>datastore</id>
            <parameters>
            <Parameter><name>dbtype</name><value>postgisng</value></Parameter>
            <!-- REMOVED DB ACCESS -->

            <Parameter><name>Expose primary keys</name><value>true</value></Parameter>
            </parameters>
        </DataStore>
    </sourceDataStores>
    <targetTypes>
        <FeatureType>
         <schemaUri>http://schemas.opengis.net/samplingSpatial/2.0/spatialSamplingFeature.xsd</schemaUri>
          <schemaUri>http://schemas.opengis.net/om/2.0/observation.xsd</schemaUri>
          <schemaUri>http://schemas.opengis.net/sampling/2.0/samplingFeature.xsd</schemaUri>
          <schemaUri>http://lab.scinfo.org.nz/static/schema/soil-data-ie/0.1/soil-data-ie.xsd</schemaUri>
                  <schemaUri>http://schemas.opengis.net/gml/3.2.1/gml.xsd</schemaUri>
        </FeatureType>
    </targetTypes>
    <typeMappings>
        <FeatureTypeMapping>
            <sourceDataStore>datastore</sourceDataStore>
            <sourceType>soil</sourceType>
            <targetElement>soil:SO_Soil</targetElement>
            <attributeMappings>
                <AttributeMapping>
                    <targetAttribute>soil:SO_Soil</targetAttribute>
                    <idExpression>
                                         <OCQL>soil_gml_id</OCQL>
                    </idExpression>
                </AttributeMapping>
                <AttributeMapping>
                    <targetAttribute>gml:identifier</targetAttribute>
                    <sourceExpression>
                        <OCQL>strConCat('http://lab.scinfo.org.nz/soil-data-ie/id/isric/soil/so_soil/',profile_id)</OCQL>
                    </sourceExpression>
                    <ClientProperty>
                            <name>codeSpace</name>
                            <value>'http://www.landcareresearch.co.nz'</value>
                        </ClientProperty>
                </AttributeMapping>

                  <AttributeMapping>
                                        <targetAttribute>gml:description</targetAttribute>
                                        <sourceExpression>
                                                <OCQL>strConCat('WOSIS profile code ',profile_code)</OCQL>
                                        </sourceExpression>
                                </AttributeMapping>

                     <AttributeMapping>
                    <encodeIfEmpty>true</encodeIfEmpty>
                                        <targetAttribute>soil:soRelatedSamplingFeature</targetAttribute>

                                </AttributeMapping>
                <AttributeMapping>
                                    <encodeIfEmpty>true</encodeIfEmpty>
                                    <targetAttribute>soil:soClassifier</targetAttribute>


                                </AttributeMapping>

                <AttributeMapping>
                                    <encodeIfEmpty>true</encodeIfEmpty>
                                    <targetAttribute>soil:soAvailableWaterCapacity</targetAttribute>
                </AttributeMapping>

                <AttributeMapping>
                                    <encodeIfEmpty>true</encodeIfEmpty>
                                    <targetAttribute>soil:soDrainage</targetAttribute>
                                </AttributeMapping>

                <AttributeMapping>
                                    <encodeIfEmpty>true</encodeIfEmpty>
                                    <targetAttribute>soil:soDepthToRock</targetAttribute>
                                </AttributeMapping>


                    <AttributeMapping>
                        <targetAttribute>soil:soHorizon</targetAttribute>
                <encodeIfEmpty>true</encodeIfEmpty>
                            <sourceExpression>

                                    <OCQL>profile_id</OCQL>
                                        <linkElement>_sohorizon</linkElement>
                                        <linkField>FEATURE_LINK</linkField>
                                  </sourceExpression>
                                   <isMultiple>true</isMultiple>

                    <ClientProperty>
                    <name>xlink:title</name>
                                        <value></value>
                   </ClientProperty>

                                   <ClientProperty>
                                       <name>xlink:href</name>

                                        <value>strConCat('http://lab.scinfo.org.nz/soil-data-ie/id/isric/soil/so_horizon/',profile_layer_id)</value>
                                    </ClientProperty>
                <ClientProperty>
                                       <name>xlink:title</name>



                    <value>layer_title</value>
                                    </ClientProperty>
                                </AttributeMapping>

            </attributeMappings>
        </FeatureTypeMapping>

        <!-- ======================================== -->
        <!-- link to gml_name datastore for multiple gml:name -->

        <!-- Feature Linking-->

        <FeatureTypeMapping>
                       <mappingName>_sohorizon</mappingName>
                        <sourceDataStore>datastore</sourceDataStore> -->

                        <sourceType>profile_layer2</sourceType>
                    <targetElement>soil:SO_Horizon</targetElement>

            <attributeMappings>
                <encodeIfEmpty>true</encodeIfEmpty>

                        <AttributeMapping>
                                <targetAttribute>FEATURE_LINK</targetAttribute>

                                <sourceExpression><OCQL>profile_id_fk</OCQL></sourceExpression>
                        </AttributeMapping>

                            <AttributeMapping>
                                <targetAttribute>soil:soHorizon</targetAttribute>
                            </AttributeMapping>

            </attributeMappings>
        </FeatureTypeMapping>

    </typeMappings>
</as:AppSchemaDataAccess>