Reset Embedded H2 database periodically

Question

I\'m setting up a new version of my application in a demo server and would love to find a way of resetting the database daily. I guess I can always have a cron job executing dro

Answer 1

As this response is the first Google result for "reset H2 database", I post my solution below :

After each JUnit @tests :

• Disable integrity constraint
• List all tables in the (default) PUBLIC schema
• Truncate all tables
• List all sequences in the (default) PUBLIC schema
• Reset all sequences

• Reenable the constraints.

  @After
  public void tearDown() {
      try {
          clearDatabase();
      } catch (Exception e) {
          Fail.fail(e.getMessage());
      }
  }
  
  public void clearDatabase() throws SQLException {
      Connection c = datasource.getConnection();
      Statement s = c.createStatement();
  
      // Disable FK
      s.execute("SET REFERENTIAL_INTEGRITY FALSE");
  
      // Find all tables and truncate them
      Set tables = new HashSet();
      ResultSet rs = s.executeQuery("SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES  where TABLE_SCHEMA='PUBLIC'");
      while (rs.next()) {
          tables.add(rs.getString(1));
      }
      rs.close();
      for (String table : tables) {
          s.executeUpdate("TRUNCATE TABLE " + table);
      }
  
      // Idem for sequences
      Set sequences = new HashSet();
      rs = s.executeQuery("SELECT SEQUENCE_NAME FROM INFORMATION_SCHEMA.SEQUENCES WHERE SEQUENCE_SCHEMA='PUBLIC'");
      while (rs.next()) {
          sequences.add(rs.getString(1));
      }
      rs.close();
      for (String seq : sequences) {
          s.executeUpdate("ALTER SEQUENCE " + seq + " RESTART WITH 1");
      }
  
      // Enable FK
      s.execute("SET REFERENTIAL_INTEGRITY TRUE");
      s.close();
      c.close();
  }
  

The other solution would be to recreatethe database at the begining of each tests. But that might be too long in case of big DB.