Fully SQL compliant

[MARTINEZ Antonio <An...@alcatel-lucent.com>]

Hello,

In our project currently we are using XPATH to query the repository.

We have a new application that would need to query the repository using
SQL.

- Is JCR170, or the extensions provided in JackRabbit 1.4 fully SQL
compliant ?

- Is there a performance difference between the two query query
languages ?


Thank-you,
Antonio

Re: Fully SQL compliant

[Jukka Zitting <ju...@gmail.com>]

Hi,

On Fri, May 30, 2008 at 4:47 AM, MARTINEZ Antonio
<An...@alcatel-lucent.com> wrote:
> - Is JCR170, or the extensions provided in JackRabbit 1.4 fully SQL
> compliant ?

No, JSR 170 specifies a relatively tight SQL subset (for example no
joins) and Jackrabbit only extends that subset a bit.

> - Is there a performance difference between the two query query
> languages ?

No. Both XPath and SQL are parsed into an abstract in-memory query
tree that the underlying query engine uses. The performance of
equivalent XPath and SQL queries is thus practically the same.

BR,

Jukka Zitting

Re: Fully SQL compliant

[Alexander Klimetschek <ak...@day.com>]

On Fri, May 30, 2008 at 3:47 AM, MARTINEZ Antonio
<An...@alcatel-lucent.com> wrote:
> - Is JCR170, or the extensions provided in JackRabbit 1.4 fully SQL
> compliant ?

No, it can't, since standard SQL works on a very different datamodel
(relational) than JCR (hierarchical). The SQL in JCR is a best-effort
mapping, but not a complete SQL. Have a look at the JCR spec, section
8.5 "Searching Repository Content with SQL".

> - Is there a performance difference between the two query query
> languages ?

None that I know of.

Regards,
Alex

-- 
Alexander Klimetschek
alexander.klimetschek@day.com