Re: [GENERAL] using hstore to store documents - Mailing list pgsql-general

On 01/28/2017 05:57 PM, Rita wrote:
> sorry for the late reply.
>
> My table schema is very simple
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> DROP TABLE xmltest;
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> create table xmltest(
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>   id serial,        -- dont really need the serial

Maybe not a serial id, but a Primary Key of some sort would help with
what you say you want to do below, I think.

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> data xml NOT null
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> );
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> INSERT INTO xmltest (data, id) VALUES ('
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> <attendee>
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>  <bio>
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>  <name>John Doe</name>
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>  <birthYear>1986</birthYear>
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>  </bio>
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>  <languages>
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>  <lang level="5">php</lang>
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>  <lang level="4">python</lang>
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>  <lang level="2">java</lang>
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>  </languages>
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> </attendee>', 1);
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> I really don't need the serial but every 30 seconds or so I plan to
> overwrite the data portion. so, I suppose I wanted a simple key/value
> thats where my orignal question stemmed from.

Why do you want to overwrite the data if you plan to refer to it below?

>
> After xmltest has been populated, I can run xpath and unest to get my
> data into a row but I would like to store that result in another table,
> I am guessing I should look into triggers for something like that?
> Eventually, I plan to have 5-6 downstream tables which will have xmltest

Why 5-6 tables?

Are they each holding some subset of data?

A schematic representation of what you are thinking of doing would help
with developing an answer to your question.

> as my head. The application will be accessing the downstream tables and
> rarely be touching xmltest (head table).
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> On Thu, Jan 26, 2017 at 10:38 AM, David G. Johnston
> <david.g.johnston@gmail.com <mailto:david.g.johnston@gmail.com>> wrote:
>
>     On Thu, Jan 26, 2017 at 5:37 AM, Rita <rmorgan466@gmail.com
>     <mailto:rmorgan466@gmail.com>>wrote:
>
>         of course, sorry for being vague.
>
>         I have an external process generating a XML file (every 30 secs)
>         which is about 10MB. I would like to store the file as XML type
>         for me to query using xpath. I plan to query it every few
>         seconds by few hundred clients. so, it maybe easier for me
>         create a separate table of my xpath results and have clients
>         query that table (xpath can be expensive).
>
>
>     ​If the XML being generated has a fixed structure/schema I
>     personally would treat the XML as a serialization format and
>     de-serialize and store it in a database as one or more relationally
>     linked tables.​  If you have to deal with the possibility of dynamic
>     structure I would still try to put the fixed items into individual
>     columns and then and then any dynamic items could be stuffed into an
>     hstore typed table.
>
>     My answer to your stated question is: what happened when you tried
>     doing that?  Documentation and a bit of experimentation goes a long
>     ways in learning.
>
>     David J.
>
>
>
>
> --
> --- Get your facts first, then you can distort them as you please.--


--
Adrian Klaver
adrian.klaver@aklaver.com