Examples
Characterization Data Model
CREATE TABLE chardm (
id SERIAL,
data XML
);
-- inserting the data
INSERT INTO chardm (data) VALUES ('
<!-- edited with XMLSpy v2005 rel. 3 U (http://www.altova.com) by bonnarel (CDS) -->
<MPFS xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:stc="http://www.ivoa.net/xml/STC/v1.30" xmlns:cha="urn:vo-characterization">
<Characterization>
<characterizationAxis>
<axisFrame>
<axisName>spatial</axisName>
<calibrationStatus>CALIBRATED</calibrationStatus>
<ucd>pos</ucd>
<unit>deg</unit>
<coordsystem ID="TT-ICRS-WAVELENGTH-TOPO">
TT-ICRS-WAVELENGTH-TOPO
</coordsystem>
<accuracy>
<statError>
<flavor>statistical error</flavor>
<ErrorRefVal>
0.00055 0.00055
</ErrorRefVal>
</statError>
</accuracy>
<independantAxis>true</independantAxis>
<numBins>16 16</numBins>
<undersamplingStatus>false</undersamplingStatus>
<regularsamplingStatus>true</regularsamplingStatus>
</axisFrame>
<coverage>
<location>
<coord>
190.37379 11.366944
</coord>
<documentation>
</documentation>
</location>
<bounds>
<limits>
190.37157 11.364722 190.37601 11.369167
</limits>
<documentation>
</documentation>
</bounds>
</coverage>
<resolution>
<unit> arcsec </unit>
<resolutionRefVal>
<ReferenceValue> 1.4 </ReferenceValue>
</resolutionRefVal>
</resolution>
<samplingPrecision>
<unit> arcsec </unit>
<samplingPrecisionRefVal>
<referenceValue>
<samplingPeriod> 1.0 </samplingPeriod>
</referenceValue>
</samplingPrecisionRefVal>
</samplingPrecision>
</characterizationAxis>
<characterizationAxis>
<axisFrame>
<axisName>time</axisName>
<calibrationStatus>UNCALIBRATED</calibrationStatus>
<ucd>time</ucd>
<unit> s </unit>
<coordsystem IDREF="TT-ICRS-WAVELENGTH-TOPO" />
<accuracy>
</accuracy>
<independantAxis>true</independantAxis>
<numBins>1</numBins>
</axisFrame>
<coverage>
<location>
<coord coordsystem_id="">
2004/24/05 22:23:58
</coord>
</location>
</coverage>
</characterizationAxis>
<characterizationAxis>
<axisFrame>
<axisName>spectral</axisName>
<calibrationStatus>CALIBRATED</calibrationStatus>
<ucd>em</ucd>
<unit> um </unit>
<coordsystem ID="SPEC-SYS">
SPEC-SYS
</coordsystem>
<accuracy>
<statError>
<flavor>statistical error</flavor>
<ErrorRefVal>
0.0001
</ErrorRefVal>
</statError>
</accuracy>
<independantAxis>true</independantAxis>
<numBins>2048</numBins>
<undersamplingStatus>false</undersamplingStatus>
<regularsamplingStatus>false</regularsamplingStatus>
</axisFrame>
<coverage>
<location>
<coord>
0.4858137
</coord>
</location>
<bounds>
<limits>
0.4140 0.56548382
</limits>
</bounds>
</coverage>
<resolution>
<unit> km/s </unit>
<resolutionRefVal>
<ReferenceValue>78.6162 </ReferenceValue>
</resolutionRefVal>
<resolutionBounds>
<limits>
48.3233
101.142
</limits>
</resolutionBounds>
</resolution>
<samplingPrecision>
<unit> km/s </unit>
<samplingPrecisionRefVal>
<ReferenceValue>
<samplingPeriod>40.0000</samplingPeriod>
</ReferenceValue>
</samplingPrecisionRefVal>
</samplingPrecision>
</characterizationAxis>
<characterizationAxis>
<axisFrame>
<axisName>flux</axisName>
<calibrationStatus>UNCALIBRATED</calibrationStatus>
<ucd>phot</ucd>
<unit> </unit>
<coordsystem ID="Pixel">
TBD
</coordsystem>
<accuracy>
<statError>
<flavor>statistical error</flavor>
<ErrorRefVal>
5.63e-17
</ErrorRefVal>
<ErrorBounds>
<ErrorLimits>
5.80e-19 1.12e-16
</ErrorLimits>
</ErrorBounds>
</statError>
</accuracy>
<independantAxis>false</independantAxis>
<undersamplingStatus>false</undersamplingStatus>
<regularsamplingStatus>true</regularsamplingStatus>
</axisFrame>
<coverage>
<location>
<coord>
2.3519587e-17
</coord>
</location>
<bounds>
<limits>
-2.8933970e-15 1.1838107e-14
</limits>
</bounds>
</coverage>
</characterizationAxis>
</Characterization>
</MPFS>
');
-- creating implicit type casts for future convenient queries
CREATE CAST (XML AS TEXT) WITHOUT FUNCTION AS IMPLICIT;
CREATE CAST (XML AS VARCHAR) WITHOUT FUNCTION AS IMPLICIT;
Simpliest queries:
-- get all <coord> elements as array of xmls
SELECT
xpath_array(data, '//coord')
FROM
chardm;
-- get second element in sequence (array) of xmls
SELECT
(xpath_array(data, '//coord'))[2]
FROM
chardm;
-- get RA of the observation (which is descendant of <Position2D> element) as a real number
SELECT xpath_number(data, '//coord/Position2D/descendant::C1/text()') FROM chardm WHERE id = 3;
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