Pavel Bortnovskiy wrote:
Hello:
I am writing an application which is using Derby as an in-memory DB:
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
m_connection =
DriverManager.getConnection("jdbc:derby:memory:testdb;create=true");
In that application I am also starting the NetworkServerControl:
try {
NetworkServerControl server = new
NetworkServerControl(InetAddress.getByName("localhost"), 1527);
server.start(new PrintWriter(System.out));
} catch (Exception e) {
logger.error(e);
}
My application seems to run happily, creating and populating tables.
All the tables are well visible from the inside the app, for instance
after "CREATE TABLE" called,
this returns cnt=1:
Statement statement = m_connection.createStatement();
ResultSet rset = statement.executeQuery(
"SELECT COUNT(*) FROM SYS.SYSTABLES WHERE
TABLENAME='SAMPLE_TABLE'");
int cnt = -1;
if (rset.next()) cnt = rset.getInt(1);
However, if I try to connect with another DB client (currently I am
using Aqua Data Studio and it's configured to connect to
jdbc:derby://localhost:1527/testdb;create=true), it connects, but the
tables created in memory are not visible (while SYS tables are):
[ snip - image ]
So, why could it be that in-memory tables aren't seen from the
"outside" and what can be done to make them visible?
Hi Pavel,
From a quick look at the code snippets you posted, it seems to me you
are not connecting to the same database.
Removing "create=true" from the client driver JDBC connection URL should
demonstrate that.
To use an in-memory database with the client driver (or a data source),
you have to use the following URL:
jdbc:derby://localhost:1527/memory:testdb (or for instance
jdbc:derby://myhost:1527/memory:/absolute/path/to/my/testdb)
I agree this isn't obvious, maybe some work can be done to improve it.
Also, there is some information about the in-memory back end at
http://wiki.apache.org/db-derby/InMemoryBackEndPrimer
Hope this helps,
--
Kristian
Much appreciated!
Regards,
Pavel Bortnovskiy.
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