SQL Server - parse GPX file - sql

Question

I'm trying to parse a GPX file within SQL Server 2019, but I'm hitting a snag with namespaces, I think.
From what I can see - if the GPX file contains :
xmlns="http://www.topografix.com/GPX/1/1"
SQL returns a NULL. But if I remove that from the GPX file, the SQL returns a string of coords - as expected.
SQL code :
DECLARE #XML TABLE (XML_COLUMN XML)
DECLARE #sqlstmt NVARCHAR(255)
DECLARE #file NVARCHAR(255) = 'd:\demo_2.gpx'
SET #sqlstmt= 'SELECT * FROM OPENROWSET (BULK ''' + #file + ''', SINGLE_CLOB) AS xmlData'
INSERT INTO #XML
EXEC (#sqlstmt)
;WITH XMLNAMESPACES ('http://www.topografix.com/GPX/1/1' AS ns), X_CTE AS
(
SELECT
T1.Name.query('.') AS Name,
T2.X_Content.query('.') AS X_Content
FROM
#XML AS X
CROSS APPLY
XML_Column.nodes('/gpx/trk') AS T1(Name)
CROSS APPLY
XML_Column.nodes('/gpx/trk/trkseg/trkpt') AS T2(X_Content)
),
XML_Data AS
(
SELECT
X_Content.value('(/trkpt/#lat)[1]', 'VARCHAR(50)') AS LAT,
X_Content.value('(/trkpt/#lon)[1]', 'VARCHAR(50)') AS LON
FROM
X_CTE
)
SELECT
STUFF((SELECT '[' + LON + ',' + LAT + ']' + ','
FROM XML_Data
WHERE 1 = 1
FOR XML PATH('')), 1, 0, '') AS mapString;
GPX file content (demo_2.gpx)
<?xml version="1.0" encoding="UTF-8"?>
<gpx creator="Garmin Connect" version="1.1"
xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/11.xsd"
xmlns:ns3="http://www.garmin.com/xmlschemas/TrackPointExtension/v1"
xmlns="http://www.topografix.com/GPX/1/1"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns2="http://www.garmin.com/xmlschemas/GpxExtensions/v3">
<metadata>
<link href="connect.garmin.com">
<text>Garmin Connect</text>
</link>
<time>2022-05-29T08:37:21.000Z</time>
</metadata>
<trk>
<name>My Route</name>
<type>e_bike_mountain</type>
<trkseg>
<trkpt lat="54.37033147551119327545166015625" lon="-3.075514398515224456787109375">
<ele>65.8000030517578125</ele>
<time>2022-05-29T11:37:02.000Z</time>
<extensions>
<ns3:TrackPointExtension>
<ns3:atemp>17.0</ns3:atemp>
<ns3:hr>155</ns3:hr>
</ns3:TrackPointExtension>
</extensions>
</trkpt>
<trkpt lat="54.37033147551119327545166015625" lon="-3.075514398515224456787109375">
<ele>65.8000030517578125</ele>
<time>2022-05-29T11:37:03.000Z</time>
<extensions>
<ns3:TrackPointExtension>
<ns3:atemp>17.0</ns3:atemp>
<ns3:hr>155</ns3:hr>
</ns3:TrackPointExtension>
</extensions>
</trkpt>
</trkseg>
</trk>
</gpx>
Really pulling the last bits of remaining hair out with this one, if anyone can assist, that would be totally awesome!

Answer 1

Your XML defines a default namespace, that is applied to all XML nodes - as long as no other namespace is defined explicitly, by means of a prefix:
<gpx creator="Garmin Connect" version="1.1"
...
xmlns="http://www.topografix.com/GPX/1/1"
The xmlns= declaration, without an alias (like xmlns:ns=...), is the default XML namespace for your XML document.
Now if you actually define your XML namespace in the query, with an alias ns like so:
;WITH XMLNAMESPACES ('http://www.topografix.com/GPX/1/1' AS ns)
then you must also use that alias in all your relevant XPath queries:
SELECT
...
FROM
#XML AS X
CROSS APPLY
XML_Column.nodes('/ns:gpx/ns:trk') AS T1(Name)
CROSS APPLY
XML_Column.nodes('/ns:gpx/ns:trk/ns:trkseg/ns:trkpt') AS T2(X_Content)
Alternatively, and much simpler - define the XML namespace as your default namespace in the XQuery in T-SQL; then you do not need to apply the namespace alias everywhere:
;WITH XMLNAMESPACES (DEFAULT 'http://www.topografix.com/GPX/1/1')
And in the end - you could write your XQuery much simpler - try this:
WITH XMLNAMESPACES (DEFAULT 'http://www.topografix.com/GPX/1/1')
SELECT
LAT = XC.value('#lat', 'VARCHAR(50)'),
LON = XC.value('#lon', 'VARCHAR(50)')
FROM
#Xml AS X
CROSS APPLY
XML_Column.nodes('/gpx/trk/trkseg/trkpt') AS XT(XC)
This should return the same value - with much less code and indirections....

Answer 2

Sorted, with many thanks to marc_s - my final working code ...
DECLARE #XML TABLE (XML_COLUMN XML)
DECLARE #sqlstmt NVARCHAR(255)
DECLARE #file NVARCHAR(255) = 'd:\erc\gpx\demo_4.gpx'
SET #sqlstmt= 'SELECT * FROM OPENROWSET ( BULK ''' + #file + ''', SINGLE_CLOB) AS xmlData'
INSERT INTO #XML
EXEC (#sqlstmt)
;WITH XMLNAMESPACES (DEFAULT 'http://www.topografix.com/GPX/1/1'), X_CTE AS
(
SELECT
LAT = XC.value('#lat', 'VARCHAR(50)'),
LON = XC.value('#lon', 'VARCHAR(50)')
FROM
#XML AS X
CROSS APPLY
XML_Column.nodes('/gpx/trk/trkseg/trkpt') AS XT(XC)
),
XML_Data AS
(
SELECT * FROM X_CTE
)
SELECT Stuff
((
SELECT
'[' + LON + ',' + LAT + ']' + ','
FROM XML_Data
WHERE 1 = 1
FOR XML PATH('')), 1, 0, '') AS mapString;