Mailing-List: contact derby-user-help@db.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Derby Discussion" <derby-user@db.apache.org>
Received-SPF: pass (nike.apache.org: local policy)
Date: Mon, 05 Jan 2009 15:51:31 +0100
From: Dag.Wanvik@Sun.COM (Dag H. Wanvik)
Subject: Re: is there a lower-level (non-SQL) API for Derby?
In-reply-to: 
 <F8C8ED1C6BC6A24D82AC1A931F6A87006238601864@PROS-EMAIL.prosrm.com>
Sender: Dag.Wanvik@Sun.COM
To: Derby Discussion <derby-user@db.apache.org>
Message-id: <x1ox7i59q00c.fsf@sun.com>
MIME-version: 1.0
Content-type: text/plain; charset=us-ascii
Content-transfer-encoding: 7BIT
References: <F8C8ED1C6BC6A24D82AC1A931F6A87006238601864@PROS-EMAIL.prosrm.com>
User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.1 (usg-unix-v)

Tim Dugan <TDugan@prospricing.com> writes:


> I'm looking to see if Derby can be used similarly to Berkeley DB --
> a lower-level API.  Can anyone tell me?

No, there is no public lower level API.

> Maybe to the access area of the "Store Layer" which in some Derby
> documentation is described like this:
>
> "The Store layer is split into two main areas, access and raw. The
> access layer presents a conglomerate (table or index)/row based
> interface to the SQL layer. It handles table scans, index scans,
> index lookups, indexing, sorting, locking policies, transactions,
> isolation levels."

Right, there are internal layers in the architecture, but they do not
constitute public APIs at the present time. Note that when you use
Derby embedded combined with prepared statements, the SQL overhead is
typically low, we have measured in the order of 15-20% extra for read
operations of small records with a simple primary key (we used the
internal APIs to make a comparison), where data fit in the in-memory
cache. But YMMV, of course.

>
> Now that Derby is included in Java 16--I am having a really hard
> time finding Java documentation that talks about Derby.

The Java DB docs are essentially the Derby docs rebundled. You can
find them here:

http://developers.sun.com/javadb/reference/docs/index.jsp

The Derby version is here:

http://db.apache.org/derby/manuals/index.html#docs_10.4

Thanks,
Dag