H2 Database is probably the best Java in-memory database. It supports different deployment mode from in-memory/embedded to standalone and clustered server. The H2 Database project is created Thomas Mueller who is also the original developer of HSQL.

Features

• included h2*.jar
• Start servlet console, standalone console, and tcp server by configuration.
• register a Spring data source
• database creation and a plugable DBInitializer model
• DBInitializer - you define a class with a init(dataSource) method and configure it in Config.groovy

Configuration

• please check the sample Config.groovy of your version at the svn repository, the following is a sample for 0.2:

  plugins { 
    h2 {
      /**
       * For console.standalone, tcpserver, and pgserver, 'disable' is a special option, and the rest are H2 Server options.
       * Check http://www.h2database.com/javadoc/org/h2/tools/Server.html#r8
       */
      console {
        servlet {
          disable = false; mapping = '/h2-console/*' //must end with '/*'
        }
        standalone { // refer to the -web* options
          disable = false; webPort = 8443; webAllowOthers = true; webSSL = true; 
        }
      }
      tcpserver { disable = false; tcpPort = 8043; tcpAllowOthers = true }
      pgserver { disable = false; pgPort = 5432; pgAllowOthers = true; baseDir = './data/h2'; trace = '' }
      database { //
        sample { // a Spring DriverManagerDataSource will be created as "${databaseName}DataSource"
          /**
           * refer to: http://www.h2database.com/html/features.html#database_url
           */
          url = "jdbc:h2:./data/h2/sample;MODE=MYSQL"; user = "sa"; //password = ""
          init {
            //disable = true; initClass = "org.grails.plugins.h2.DBInitializer" // create a new instance and call its init( dataSource) method  
          }
        }
      }
    }
  }
  

• Notice: if you to disable a feature, you should omit a configuration rather than set it to false
• Sample dataSource configuration, refer to H2 Docs about URL:

  dataSource { 
  	pooled = false; //it is recommended not to use connection pool unless file encryption is enabled 
  	driverClassName = "org.h2.Driver" 
  	username = "sa" 
  	password = "" 
  } 
  
  // environment specific settings 
  environments { 
  	development { 
  		dataSource { 
  			dbCreate = "create-drop" // one of 'create', 'create-drop','update' 
  			url = "jdbc:h2:mem:devDB" 
  		} 
  	} 
  	test { 
  		dataSource { 
  			dbCreate = "update" 
  			url = "jdbc:h2:mem:testDb" 
  		} 
  	} 
  	production { 
  		dataSource { 
  			dbCreate = "update" 
  			url = "jdbc:h2:file:~/.h2" //or any other path 
  		} 
  	} 
  } 
  

Version and Compatibility

• remarks: h2 has a short release period that new version comes out maybe more than once per month. you are recommended to download and replace the h2*.jar in your local project, and inform the Author to release an update if there are major changes.
• The plugin is tested with Grails 1.1 beta 3
• Refer to the CHANGES.txt for update history

roadmap

• refer to the TODO.txt for planned tasks

Author: Mingfai Ma (mingfai.ma at gmail dot com)