topic Re: Pulling the tag string nodes in the metadata... in App Development

Pulling the tag string nodes in the metadata...

markperrone — Fri, 12 May 2023 17:29:01 GMT

I used the data manager to open a qvd as XML.

It showed a table with all the tag/string nodes.

Tags:
LOAD
[String%Table],
[%Key_QvdFieldHeader_59D66ED49CFF179D]
FROM $(vFileName)
(XmlSimple, table is [QvdTableHeader/Fields/QvdFieldHeader/Tags/String]);

When I inspect the qvd, I don't see the key_qvdfieldheader_59D66ED49CFF179D.

Is there some good documentation on qvd metadata ?

Re: Pulling the tag string nodes in the metadata...

Vegar — Fri, 12 May 2023 19:26:30 GMT

I haven't seen any official documentation of the QVD XML header, but you could take a look at @stevedark 's old blogpost How To Read Meta Data From A QlikView QVD. It can help you getting started.

https://www.quickintelligence.co.uk/read-meta-data-qlikview-qvd/

Re: Pulling the tag string nodes in the metadata...

stevedark — Fri, 12 May 2023 20:06:33 GMT

Hi @Vegar

Thanks for sharing the link to my post.

There is also a full script included with my Instant Sense Application which loops all QVDs in a library and pulls in the metadata from each of them.

Steve

Re: Pulling the tag string nodes in the metadata...

markperrone — Thu, 18 May 2023 15:16:21 GMT

Hi Steve

I looked through ISA and didn't see a reference to the tag elements. From I can research there are %key elements in the xml I can use to collect the tags. Are these elements the same across all QVDs ?

%Key_QvdFieldHeader_59D66ED49CFF179D

%Key_QvdTableHeader_B94FCCAC68ED3E20

I tried a few and they appear to be consistent. Anyone tried to work with these two keys ?

Re: Pulling the tag string nodes in the metadata...

stevedark — Fri, 19 May 2023 10:45:34 GMT

Hi @markperrone

I've not included those in the ISA as I wanted to ensure that it would work over any QVD, in fact the script was first written years ago over QlikView QVDs.

Saying that, each QVD I have looked at which is half recent has both of those fields in with exactly the same field name. I've dug up a 13 year old QVD and it only has the Table Header field, but that has the exact same field name.

Everywhere I have seen, the table header only contains zero, whilst the field header contains ascending numbers as you go down the list of fields - my guess is it is the start position of the field in the QVD. That would be easily checked out - but I've not done it.

What are you hoping to get from these fields?

If you want a decade old post from @hic talking French (I think) on the topic there is this:

https://community.qlik.com/t5/QlikView-App-Dev/script-qlikview/m-p/562906

Also this post references the field:

https://community.qlik.com/t5/QlikView-App-Dev/How-to-use-QVD-file-functions-in-the-script/m-p/929199

There does not seem to be a lot written about those fields though, as far as I can see.

Steve