In-memory databases
are the databases which reside in main memory.These databases either
partially or fully lack the durability property of ACID (atomicity, consistency,isolation and durability).
In-memory databases are used when either we want very quick performance or in the cases where data
used in application does not need to be durable. While developing the testcases
of DAO layer, in memory database in embedded mode is preferred. This provide quick access and full control of
databases in the test.
In the arena of in-memory databases H2 has it significant
presence.It can be included in the application using maven dependency and can be
run in imbedded or standalone mode.
Maven Dependency
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<version>1.3.167</version>
</dependency>
Bean configuration to start and stop the H2 database along with spring bean factory creation and destroy
<bean id = "org.h2.tools.Server"
class="org.h2.tools.Server"
factory-method="createTcpServer"
init-method="start"
destroy-method="stop">
<constructor-arg value="-tcp,-tcpAllowOthers,true,-tcpPort,8043" />
</bean>
H2 default connection details
driver - org.h2.Driver
Hibernate Dialect -org.hibernate.dialect.H2Dialect
jdbc url -jdbc:h2:~/test
user name - sa
password -
Starting server from command
line-
java -cp h2-1.3.167.jar org.h2.tools.Server
Shutting down server from
command line –
Basic setup to use H2 in unit testing -To use H2 in unit test cases, we might want to extend H2DBEnabledTestCase class, which starts the H2 server in setup method so that during test run database could be available and stops server in tearDown method.
While including H2 in our application, we implemented facade for performing H2 related interactions and operations.
java -cp h2-1.3.167.jar org.h2.tools.Server -tcpShutdown tcp://localhost:909
Basic setup to use H2 in unit testing -To use H2 in unit test cases, we might want to extend H2DBEnabledTestCase class, which starts the H2 server in setup method so that during test run database could be available and stops server in tearDown method.
import java.sql.SQLException;
import org.h2.tools.Server;
import junit.framework.TestCase;
public abstract class H2DBEnabledTestCase extends TestCase {
private Server httpServer;
@Override
protected void setUp() throws SQLException {
httpServer = Server.createTcpServer(
new String[] { "-tcpPort", "8080", "-tcpAllowOthers" }).start();
}
@Override
protected void tearDown() {
if (httpServer != null && httpServer.isRunning(false)) {
httpServer.stop();
}
}
}
In-memory jdbc url - jdbc:h2:mem:test;DB_CLOSE_DELAY=-1
While including H2 in our application, we implemented facade for performing H2 related interactions and operations.
Sample use of H2 using above
mentioned facade
Running application of above code can be downloaded from here . You will need java 6.0 and maven 3 to get the application running.
Kindly follow below mentioned steps to see it in execution –
Running application of above code can be downloaded from here . You will need java 6.0 and maven 3 to get the application running.
Kindly follow below mentioned steps to see it in execution –
- Download the application and extract it.
- Execute mvn eclipse:eclipse by traversing to the location of pom.xml
- Import the application in eclipse
- Run H2ServerTest.java as Junit test.
Reference
http://www.h2database.com/html/tutorial.html
http://en.wikipedia.org/wiki/In-memory_database
