Delphi7 - OmniXML - select specific node with multiple parameters - delphi

Question

XML file:
<Partner>
...
</Partner>
<Partner>
<K1>10</K1>
<K2>3</K2>
<K3>5254304</K3>
<K4>test name</K4>
<K5>637.51</K5>
<K6>159.38</K6>
<K7>802.39</K7>
<K8>0.00</K8>
<K9>802.39</K9>
<Invoices>
<Invoice>
<R1>1</R1>
<R2>4-02R0113-12</R2>
<R3>2014-12-29</R3>
<R4>2014-12-29</R4>
<R5>398</R5>
<R6>637.51</R6>
<R7>159.38</R7>
<R8>802.39</R8>
<R9>0.00</R9>
<R10>802.39</R10>
</Invoice>
</Invoices>
</Partner>
<Partner>
...
</Partner>
In my XML file I have repeating nodes <Partner>. Every partner has its own identification number written in node <K3>.
Every partner can have multiple invoices.
I need to find and read values in <R6> and <R7> in the invoice where
I know values for <R2>, <R3>, <R8>.
How do I search for specific Invoice where search criteria are multiple fields <R2>, <R3>, <R8> of partner where search criteria is field <K3> and get field values for <R6> and <R7>?
How to add multi criteria to SelectSingleNode?
My code:
procedure TfrmTest.TestReadOmniXML;
var
xml: IXMLDocument;
iNodePartner, iNodePartnerInvoice, iNodePartnerInvoiceR6, iNodePartnerInvoiceR7 : IXMLNode;
begin
xml := CreateXMLDoc;
xml.Load('c:\test.xml');
iNodePartner := XML.SelectSingleNode('//Partner[K3=' + '0254304' + ']');
iNodePartnerInvoice := iNodePartner.SelectSingleNode(
//single query works OK
'.//Racuni/Racun[R2=' + '4-02R0113-12' + ']'
//but I need to add these fields also
// ' and [R3=' + '2014-12-29' + ']' +
// ' and [R8=' + '802.39' + ']'
);
if Assigned( iNodePartnerInvoice ) then
begin
iNodePartnerInvoiceR6 := iNodePartnerInvoice.SelectSingleNode('./R6');
Label1.Caption := iNodePartnerInvoiceR6.Text;
iNodePartnerInvoiceR7 := iNodePartnerInvoice.SelectSingleNode('./R7');
Label2.Caption := iNodePartnerInvoiceR7.Text;
end;
...
end;

Answer 1

OmniXMLXPath doesn't support that out of the box. I have, however, added support for consecutive filters last year, but forgot to push that change to the public site :(
With the updated version, this will work:
program Project29;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
OmniXML,
OmniXMLXpath,
OmniXMLUtils;
var
xml: IXMLDocument;
node: IXMLNode;
begin
xml := CreateXMLDoc;
if XMLLoadFromFile(xml, 'c:\0\partner.xml') then begin
node := xml.SelectSingleNode('//Partner/Invoices/Invoice[R2="4-02R0113-12"][R3="2014-12-29"][R8="802.39"]');
if not assigned(node) then
Writeln('not found')
else begin
Writeln('R6=', GetNodeTextStr(node, 'R6', ''));
Writeln('R7=', GetNodeTextStr(node, 'R7', ''));
end;
end;
Readln;
end.
For now, you can get the fresh OmniXMLXPath.pas here: https://www.dropbox.com/s/nnvrz6wnmnpmxzn/OmniXMLXPath.pas

Answer 2

Given the example above, you can do something along the lines of:
//Partner[K2=3]/Invoices/Invoice[R1=1 and R5=398]
This gets the Ivoices of partner with K2=3 where ivoices have specific values for r1 and r5. Then, depending on how you need to process the invoices that match these criteria (e.g. if there is more than one invoice) you can then use an XPath expression (like sum or something else) to return a single value calculated from these Invoice elements.

Answer 3

Accordingly OmniXMLXPath.pas file, OmniXML does not support logical operation in XPath. So you can't search by 2+ attributes simultaneously.
You can select multiple nodes by calling SelectNodes('//Partner[K3=5254304]/Invoices/Invoice[R2='4-02R0113-12']) and check nodes by another attributes.
Or use MSXML parser (OmniXML_MSXML unit) if you can. This will work on your demo data:
procedure TForm1.Button1Click(Sender: TObject);
var
xml: IXMLDocument;
iNodePartner: IXMLNode;
begin
xml := CreateXMLDoc;
xml.Load('c:\test.xml');
iNodePartner := XML.selectSingleNode('//Partner[K3=5254304]/Invoices/Invoice[R2=''4-02R0113-12'' and R8=''802.39'']');
if iNodePartner = nil then
MessageDlg('Not found',mterror,[mbok],0);
end;