How to suppress an empty tag in the XML

Question

Hi gurus,
Please help me with this problem. A part of my XML output looks like this,
<ParentElement>
<ChildElement>The Data</ChildElement>
<ChildElement>The Data</ChildElement>
</ParentElement>
This is produced in a select XMLAgg() statement from a table. If the table has one or more rows, I get the above result. But if there is no data in the table, I will get
<ParentElement/>. But the schema is such that if the ParentElement is there, it requries at least one ChildElement so the XML file does not validate. Is there a way to suppress the ParentElement when there is no data in the table? Or should the schema be changed?
Thanks a lot.
Ben

Answer 1

Thank you very much for your fast response. Here is the code that I use to generate the XML. At issue is the "PersonPhysicalFeature" element.
create or replace function fnGetLivescanDataForBCA (
     p_BookingNo     in     varchar2,
     p_MniID          in     number
return Clob
as
     v_XMLForBCA                    Clob := null;
     v_BookingAgencyORI      constant     varchar2(10) := '0620000';
     v_DateFormat          constant     varchar2(10) := 'mm/dd/yyyy';
     v_DateTimeFormat     constant     varchar2 (25) := 'mm/dd/yyyy hh24:mi';
     v_BCADateFormat          constant     varchar2(10) := 'yyyymmdd';
     v_UnknownBOP          constant     varchar2(2) := 'XX';
     v_UnknownCC          constant     varchar2(2) := 'XX';
     v_XMLFile                    XMLType;
     v_created                    boolean := false;
     --- BCA insists on having the XML prolog
     v_XMLProlog constant varchar2(100) := '<?xml version="1.0" encoding="UTF-8"?>' || utl_tcp.CRLF ;     
begin
     select XMLElement("BookSubject",
          XMLForest('DAVE FENNER' as "AttentionPerson"),
          XMLElement("AttentionOrganization",
               XMLForest(v_BookingAgencyORI as "OrganizationORIID")
          XMLForest('N' as "PalmprintAvailableIndicator",
               'Y' as "ArrestPhotoAvailableIndicator",
               'ARMED AND DANGEROUS' as "IdentificationComments",
               'N' as "InterstateCustodyTransferInd",
               '192.168.95.11' as "SourceComputerSystemAddress"),
          XMLElement("Booking",
               XMLForest(to_char(b.arrival_date, v_BCADateFormat ) as "ActivityDate"),               
               XMLElement("BookingAgencyRecordID",
                    XMLForest(substr(b.booking_no, 1, 4) || substr(b.booking_no, 7,6) as "ID")                         
               XMLElement("BiometricDeviceRecordID",
                    XMLForest(b.booking_no as "ID")
               XMLElement("BookingAgency",
                    XMLForest(v_BookingAgencyORI as "OrganizationORIID")
               XMLElement("BookingSubject",
                    (select XMLElement("PersonName",
                              XMLForest(substr(first_name, 1, 30) as "PersonGivenName",
                                   substr(middle_name, 1,30) as "PersonMiddleName",
                                   substr(last_name,1, 30) as "PersonSurName")
                         from name
                         where mni_id = p_MniID
                         ),-- end of select name                    
                    (select XMLElement("PersonBirthDate",
                              to_char(m.dob, v_BCADateFormat)
                         from name m                         
                         where m.mni_id = p_MniID                    
                         ), -- end of select alias
                    (select XMLAgg(
                              XMLElement("PersonBirthDate",
                                   to_char(ma.alias_dob, v_BCADateFormat)
                         ) -- end of XMLAgg - required for multiple rows     
                         from name_alias ma     
                         where ma.mni_id = p_MniID
                         ), -- end of select alias dob
                    (select XMLElement("PersonBirthLocationCode",
                              NVL(m.birth_state, v_UnknownBOP))
                         from name m
                         where m.mni_id = p_MniID
                         ), -- end of select birth state
                    XMLElement("PersonAssignedIDDetails",
                         (select XMLElement("PersonSSNID",
                                   XMLForest(m.ssn as "ID")
                              from name m
                              where m.mni_id = p_MniID
                              ), -- end of select name.ssn     
                         (select XMLAgg(
                                   XMLElement("PersonSSNID",
                                        XMLForest(ms.ssn as "ID")
                                   ) -- end of XMLAgg
                              from name_ssn ms
                              where ms.mni_id = p_MniID and rownum <= 3               
                              ), -- end of select alias SSN
                         (select XMLElement("PersonOtherID",
                                   XMLElement("ID", m.slco_pin),
                                   XMLElement("IDSourceOrganization",
                                        XMLForest(v_BookingAgencyORI as "OrganizationORIID")
                              from name m
                              where m.mni_id = p_MniID
                              ), -- end of select name.slco_pin as OtherID
                         XMLElement("BookingAgencyPersonID",
                              XMLForest('123456789' as "ID",
                                   'RCSO Some ID' as "IDTypeDescriptionText"),
                              XMLElement("IDSourceOrganization",
                                   XMLForest(v_BookingAgencyORI as "OrganizationORIID")
                              ) -- end of BookingAgencyPersonID
                         ), -- end of ID Details     
                    (select XMLElement("PersonPhysicalDetails",
                              XMLForest(m.eye_color as "PersonEyeColorCode",
                                   m.hair_color as "PersonHairColorCode",
                                   m.sex as "PersonSexText",
                                   m.race as "PersonRaceCode"),                              
                              XMLElement("PersonPhysicalFeature",
                                   (select XMLAgg(
                                             XMLElement("PhysicalFeatureDescriptionText",
                                                  substr(smt.bodypart || ' ' || smt.description, 1, 10)
                                                  ) -- end of feature desc text
                                             ) -- end of XMLAgg
                                        from name_smt smt
                                        where smt.mni_id = p_MniID and rownum <= 10
                                        ) -- end of select smt
                                   ), -- end of element physical feture                              
                              XMLElement("PersonHeightMeasure",
                                   XMLForest(NVL(to_char(m.height_feet), '0') || lpad(NVL(to_char(m.height_inches), '0'), 2, '0') as "Measure")
                                   ), --- end of height                         
                              XMLElement("PersonWeightMeasure",
                                   XMLForest(m.weight as "Measure")
                                   ) -- end of weight
                              ) -- end of first element                         
                         from name m
                         where m.mni_id = p_MniID
                         ), -- end of select physical details
                    (select XMLElement("PersonBiometricDetails",
                              XMLelement("PersonFingerprintSet",
                                   XMLForest(Decode(m.PERSONTYPE, 1, 'A', 2, 'J', 3, 'C', 'A')
                                   as "BiometricDescriptionText")
                                   ) -- end of second element
                              ) -- end of first element
                         from name m
                         where m.mni_id = p_MniID
                         ), -- select PersonType               
                    (select XMLAgg(
                              XMLElement("PersonAlias",
                              XMLElement("PersonName",
                                   XMLForest(substr(ma.first_name, 1, 30) as "PersonGivenName",
                                   substr(ma.middle_name, 1, 30) as "PersonMiddleName",
                                   substr(ma.last_name, 1, 30) as "PersonSurName"))
                              ) -- end of element
                         ) -- end of AMLAgg
                         from name_alias ma
                         where ma.mni_id = p_MniID
                         ), -- end of select name_alias
                    XMLElement("SubjectSupervision",
                         XMLElement("SupervisionSubjectStatus",
                              XMLForest(to_char(b.date_booked, v_BCADateFormat) as "StatusDate",
                                   'FROM RAMSEY COUNTY LEC' as "StatusDescriptionText")
                         ) -- end pf element subject supervision
                    ---XMLelement("PersonCitizenshipCode",
                    --     v_UnknownCC
                    --     ) -- end of element
                    ), -- end of BookingSubject
                    XMLElement("TreatAsAdultIndicator", 'Y'),
                    (select XMLAgg(
                              XMLElement("BookingCharge",
                                   XMLElement("ChargeText", substr(ct.statute_no, 1, 25)),
                                   XMLElement("ChargeDescriptionText", substr(trim(ct.charge), 1, 60)),
                                   XMLElement("ChargeClassification",
                                        XMLForest(ct.class as "ChargeDegreeText")),
                                   XMLElement("ChargeInstrument",
                                        XMLElement("DocumentDescriptiveMetadata",
                                             XMLForest(ct.complaint_no as "DocumentID"))),
                              ---     XMLElement("ChargeSentence", ' '),     --- do not include
                                   XMLElement("ChargeStatute",
                                        XMLForest('C' as "StatuteOffenseCode")),
                                   XMLElement("ChargeCommentsText", substr(ct.comments, 1, 50)),
                                   XMLElement("OffenseDate",
                                        to_char(NVL(ad.ucr_reported_date, ad.date_arrested), v_BCADateFormat)),
                                   XMLElement("ChargeOriginatingAgencyRID", ct.complaint_no),
                                   XMLElement("ChargeOriginatingAgency",
                                        XMLForest(ct.originating_agency as "OrganizationORIID")
                                   XMLElement("ArrestDispositionText", '205')
                         ) -- end of XMLAgg
                         from charges_temp ct
                         where ct.booking_no = p_BookingNo and ct.charge is not null
                              and length(ct.complaint_no) <= 8
                         ), -- end of select charges
               XMLElement("ArrestAgency",
                    XMLForest(NVL(ad.arresting_agency, v_BookingAgencyORI) as "OrganizationORIID"))
               ), --- end of Booking
          XMLElement("BCACriminalHistoryRequestInd", 'N'),
          XMLElement("FBICriminalHistoryRequestInd", 'N'),
          XMLElement("WantWarrantSearchRequestInd", 'N')
          ) into v_XMLFile      --- .getClobVal() into v_XMLForBCA --- v_XMLFile      ----- end of BookSubject
     from Booking b
     inner join arrest_affidavit ad
     on b.booking_no = ad.booking_no     
     where b.booking_no = p_BookingNo;
     ---v_created := DBMS_XDB.createResource('/public/' || p_BookingNo || '.xml', v_XMLFile);
     v_XMLForBCA := v_XMLFile.getClobVal();
     v_XMLForBCA := v_XMLProlog || v_XMLForBCA;     
     v_XMLFile.isSchemaValid('http://isora1.co.ramsey.mn.us:8080/sys/schemas/SSI/Schema.xsd');
     if v_XMLFile.isSchemaValid = 1 then
          dbms_output.put_line('XML is valid');
     else
          dbms_output.put_line('XML is not valid');
     end if;
     return v_XMLForBCA;
exception
     when others then
          dbms_output.put_line(SQLErrM(SQLcode));
          return null;
end fnGetLivescanDataForBCA;
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