Metadata in SQL

Question

Hi,
I have a PL-SQL procedure that is doing some smart polygons and other types of selections and saves the results into temporary table which I then include in a base map and generate with different style to mark the selection. At the moment it's however selecting even some features that are currently not visible in the map. Is there any way how can I easily parse the definition from MDSYS.USER_SDO_MAPS and get the information about min and max scales out of it? It's stored in that xml format and I couldn't find any easy way to get it out.
Thanks
Jan

Answer 1

Hi Jan,
This PL/SQL sample code may help you extract elements from an XML document. It uses the xmltype database type.
The sample creates a dummy xml document from some text - I suspect you would use the table/column you mention.
declare
xml_char varchar2(1024);
xml xmltype;
v_type varchar2(32);
v_server varchar2(32);
v_port varchar2(32);
begin
-- create dummy XML document
xml_char := '<?xml version="1.0" encoding="Cp1252"?>'||
'<CONNECTION>'||
' <MAPSERVER type="Arcims">'||
' <HOST>uranus</HOST>'||
' <PORT>5300</PORT>'||
' </MAPSERVER>'||
'</CONNECTION>';
-- convert to XML from char type
xml := xmltype.createxml(xml_char);
-- extract some elements
v_type := xml.extract('/CONNECTION/MAPSERVER/@type').getStringVal();
v_server := xml.extract('/CONNECTION/MAPSERVER/HOST/text()').getStringVal();
v_port := xml.extract('/CONNECTION/MAPSERVER/PORT/text()').getStringVal();
-- display them
dbms_output.put_line('Type = '||v_type);
dbms_output.put_line('Server = '||v_server);
dbms_output.put_line('Port = '||v_port);
end;
Excuse the crud formatting. I hope you can understand it!
Hope this helps,
Steve