View content of H2 or HSQLDB in-memory database

Question

Is there a way to browse the content of an H2 or an HSQLDB in-memory database for viewing? For example, during a debugging session with Hibernate in order to check when the

Answer 1

I've a problem with H2 version 1.4.190 remote connection to inMemory (as well as in file) with Connection is broken: "unexpected status 16843008" until do not downgrade to 1.3.176. See Grails accessing H2 TCP server hangs

Answer 2

What about comfortably viewing (and also editing) the content over ODBC & MS-Access, Excel? Softwareversions::

• H2 Version:1.4.196
• Win 10 Postgres ODBC Driver Version: psqlodbc_09_03_0210
• For Win7 ODBC Client: win7_psqlodbc_09_00_0101-x64.msi

H2 Server:

/*
For JDBC Clients to connect:
jdbc:h2:tcp://localhost:9092/trader;CIPHER=AES;IFEXISTS=TRUE;MVCC=true;LOCK_TIMEOUT=60000;CACHE_SIZE=131072;CACHE_TYPE=TQ
*/
public class DBStarter {
    public static final String BASEDIR = "/C:/Trader/db/";
    public static final String DB_URL = BASEDIR + "trader;CIPHER=AES;IFEXISTS=TRUE;MVCC=true;LOCK_TIMEOUT=10000;CACHE_SIZE=131072;CACHE_TYPE=TQ";

  static void startServer() throws SQLException {
        Server tcpServer = Server.createTcpServer(
                "-tcpPort", "9092",
                "-tcpAllowOthers",
                "-ifExists",
//                "-trace",
                "-baseDir", BASEDIR
        );
        tcpServer.start();
        System.out.println("H2 JDBC Server started:  " + tcpServer.getStatus());

        Server pgServer = Server.createPgServer(
                "-pgPort", "10022",
                "-pgAllowOthers",
                "-key", "traderdb", DB_URL
        );
        pgServer.start();
        System.out.println("H2 ODBC PGServer started: " + pgServer.getStatus());

    }
}   

Windows10 ODBC Datasource Configuration which can be used by any ODBC client: In Databse field the name given in '-key' parameter has to be used.

Answer 3

With HSQLDB, you have several built-in options.

There are two GUI database managers and a command line interface to the database. The classes for these are:

org.hsqldb.util.DatabaseManager
org.hsqldb.util.DatabaseManagerSwing
org.hsqldb.cmdline.SqlTool

You can start one of the above from your application and access the in-memory databases.

An example with JBoss is given here:

http://docs.jboss.org/jbpm/v3.2/userguide/html/ch07s03.html

You can also start a server with your application, pointing it to an in-memory database.

org.hsqldb.Server

Answer 4

For H2, you can start a web server within your code during a debugging session if you have a database connection object. You could add this line to your code, or as a 'watch expression' (dynamically):

org.h2.tools.Server.startWebServer(conn);

The server tool will start a web browser locally that allows you to access the database.

Answer 5

This is a Play 2 controller to initialize the H2 TCP and Web servers:

package controllers;

import org.h2.tools.Server;
import play.mvc.Controller;
import play.mvc.Result;

import java.sql.SQLException;

/**
 * Play 2 controller to initialize H2 TCP Server and H2 Web Console Server.
 *
 * Once it's initialized, you can connect with a JDBC client with
 * the URL `jdbc:h2:tcp://127.0.1.1:9092/mem:DBNAME`,
 * or can be accessed with the web console at `http://localhost:8082`,
 * and the URL JDBC `jdbc:h2:mem:DBNAME`.
 *
 * @author Mariano Ruiz <mrsarm@gmail.com>
 */
public class H2ServerController extends Controller {

    private static Server h2Server = null;
    private static Server h2WebServer = null;

    public static synchronized Result debugH2() throws SQLException {
        if (h2Server == null) {
            h2Server = Server.createTcpServer("-tcp", "-tcpAllowOthers", "-tcpPort", "9092");
            h2Server.start();
            h2WebServer = Server.createWebServer("-web","-webAllowOthers","-webPort","8082");
            h2WebServer.start();
            return ok("H2 TCP/Web servers initialized");
        } else {
            return ok("H2 TCP/Web servers already initialized");
        }
    }
}

Answer 6

You can run H2 web server within your application that will access the same in-memory database. You can also access the H2 running in server mode using any generic JDBC client like SquirrelSQL.

UPDATE:

Server webServer = Server.createWebServer("-web,-webAllowOthers,true,-webPort,8082").start();
Server server = Server.createTcpServer("-tcp,-tcpAllowOthers,true,-tcpPort,9092").start();

Now you can connect to your database via jdbc:h2:mem:foo_db URL within the same process or browse the foo_db database using localhost:8082. Remember to close both servers. See also: H2 database in memory mode cannot be accessed by Console.

You can also use Spring:

<bean id="h2Server" class="org.h2.tools.Server" factory-method="createTcpServer" init-method="start" destroy-method="stop" depends-on="h2WebServer">
    <constructor-arg value="-tcp,-tcpAllowOthers,true,-tcpPort,9092"/>
</bean>
<bean id="h2WebServer" class="org.h2.tools.Server" factory-method="createWebServer" init-method="start" destroy-method="stop">
    <constructor-arg value="-web,-webAllowOthers,true,-webPort,8082"/>
</bean>

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close" depends-on="h2Server">
    <property name="driverClass" value="org.h2.Driver"/>
    <property name="jdbcUrl" value="jdbc:h2:mem:foo_db"/>
</bean>

BTW you should only depend on assertions and not on manual peeking the database contents. Use this only for troubleshooting.

N.B. if you use Spring test framework you won't see changes made by a running transaction and this transaction will be rolled back immediately after the test.