Philippe Lamote wrote:
Hi List,
I'm new to Derby so if this is too trivial, don't mind rubbing my nose
into it ;-)
I have in my setup one place where I keep all the configuration
together. (jdoconfig.properties, Spring Configuration, ... )
Of course this would be the obvious place to also put the
"derby.properties". Yet this is not the place where I put the Derby data
files themselves.
So, in short, this would be the "package" layout:
- src/.../conf/derby.properties (will be copied to bin/.../conf @
compile time)
- data/... (the Derby data dir)
But then I read in the derby Manual: "You can set persistent system-wide
properties in a text file called /derby.properties/, which
must be placed in the directory specified by the /derby.system.home/
property."
I understand that "derby.system.home" would be this data directory and
this is not where I want to put the Derby properties.
I thought of this to solve it: in the general Application init method,
adding this:
<snip example of setting system properties programmatically>
--> Is this OK for Derby? And will the properties specified there indeed
be set & active upon the next connect? (and not make it put all the dat
files in my conf folder)
Yes, I think this will work, as long as you connect to the database (or start
an embedded Derby server) from the same instance of the JVM.
I would, however, like to point out that properties specified
programmatically (which is your solution) have higher precedence than
properties that are automatically picked up by Derby from the
derby.properties file; see the Derby Tuning Guide,
http://db.apache.org/derby/docs/dev/tuning/. This may be a corner case, but:
Quoting http://db.apache.org/derby/docs/dev/tuning/ctunsetprop23308.html:
<quote>
This means, for example, that system-wide properties set programmatically
override database-wide properties and system-wide properties set in the
derby.properties file, and that database-wide properties override system-wide
properties set in the derby.properties file.
</quote>
So, if (for example) you previously relied on database-wide properties
overriding system-wide properties in the derby-properties file as it was
automatically picked up by Derby, you will find that this no longer happens,
since the properties are set programmatically instead, thus overriding the
database-wide properties.
Another possible work-around is to specify "full" database paths (absolute or
relative to derby.system.home), see
http://wiki.apache.org/db-derby/DatabaseNamesRelativeAbsolute.
--
John
