code: public static void dropPrimaryKey (Connection conn, String table)
          throws SQLException
      {
          String update = "ALTER TABLE " + table + " DROP PRIMARY KEY";
          PreparedStatement stmt = null;
          try {
              stmt = conn.prepareStatement(update);
              if (stmt.executeUpdate() == 1) {
                  log.info("Database primary key removed from '" + table + "'.");
              }
          } finally {
              close(stmt);
          }
      }
docs: Removes the primary key from the specified table.