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https://issues.apache.org/jira/browse/DERBY-5466?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14709215#comment-14709215
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DM.sbs.gmail commented on DERBY-5466:
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Hi scott,
sorry I was a bit rushed the other day, so a better explanation now coming.
R is a stats analysis package that is Open source, well developed (see
https://www.r-project.org/)
There exist a number of methods to access R from a java app
Via R-Serve (effectively and instance of R running as a server) ~ I found a
quick howto here :
http://www.algosome.com/articles/running-r-code-in-java.html, and some docs
on the Rserve page (http://www.rforge.net/Rserve/).
Alternatively it seems someone has decided to created a GUI for R in Java,
see here AKA JGR: https://www.rforge.net/JGR/
or there is Decuder (
http://www.deducer.org/pmwiki/pmwiki.php?n=Main.DeducerManual) which seem
to run on top of JGR
The issue with the above is that they will require a way to start R Server
from within derby (a system call maybe ?), and both the gui systems seem to
need to be started from within a running R session.
An advantage is implementers can just add Derby and R as a server on thier
system,
Reading the R serve page they suggest that using JRI (
http://www.rforge.net/JRI/) may be possible from within any java app, by
including the required R libraries.
The big issue for me is that last releases for the various above items all
seems to be a few years ago.... but then R doesn't develop that quickly
either, but does have an active community.
Well anyway I hope the above helps somehow, it doesn't seem sensible to
re-invent the wheel for stats when it has be done in R already, Also
reading further down this thread it seems that there are potential issues
with the methods for the analysis that can be used, if Stats do need to be
included in a 'native' manner for the SQL standard, I guess that is
different,
On Sun, Aug 23, 2015 at 11:57 PM, Scott Lewis (JIRA) <[email protected]>
> Add support for SQL Standard statistics functions, such as STDDEV_POP,
> STDDEV_SAMP, VAR_POP, VAR_SAMP
> -----------------------------------------------------------------------------------------------------
>
> Key: DERBY-5466
> URL: https://issues.apache.org/jira/browse/DERBY-5466
> Project: Derby
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 10.8.1.2
> Reporter: Lukas Eder
> Priority: Minor
> Labels: derby_triage10_10
> Attachments: DERBY-5466.stats.patch,
> derby-5466-01-aa-aggregatorClasses.diff, derby-5466-02-aa-bindLogic.diff,
> derby-5466-02-ab-bindLogic.diff, derby-5466-03-aa-distinctError.diff,
> var_pop_formulas.txt
>
>
> Any of these RDBMS support the SQL standard statistics functions STDDEV_POP,
> STDDEV_SAMP, VAR_POP, VAR_SAMP:
> - DB2 (only STDDEV, VARIANE)
> - H2
> - HSQLDB
> - Ingres
> - MySQL
> - Oracle
> - Postgres
> - SQL Server (named STDEVP, STDEV, VARP, VAR)
> - Sybase ASE
> - Sybase SQL Anywhere
> These don't:
> - Derby
> - SQLite
> This would be a useful addition for Derby, I think.
> An even larger example list of possible statistics aggregate functions is
> listed in the Postgres documentation:
> http://www.postgresql.org/docs/9.0/static/functions-aggregate.html#FUNCTIONS-AGGREGATE-STATISTICS-TABLE
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