code: @Override
      protected boolean i_updateRow(Connection conn,
                                    String table,
                                    String[] columns,
                                    String[] values,
                                    String uniqueColumn,
                                    boolean[] numeric) throws SQLException {
  
          // prepare update statement
          StringBuilder sql = new StringBuilder(64);
          sql.append("UPDATE ").append(table).append(" SET ");
          boolean needComma = false;
          for (int i = 0; i < columns.length; i++) {
              if (!columns[i].equals(uniqueColumn)) {
                  if (needComma) {
                      sql.append(", ");
                  } else {
                      needComma = true;
                  }
                  sql.append(columns[i] + " = ");
                  if (values[i] == null) {
                      sql.append("NULL");
                  } else {
                      sql.append('?');
                  }
              }
          }
          sql.append(" WHERE ");
          sql.append(uniqueColumn);
          sql.append(" = ?");
          if (logger.isDebugEnabled()) {
              logger.debug("About to execute: " + sql.toString());
          }
          PreparedStatement stmt = conn.prepareStatement(sql.toString());
  
          try {
              // populate values
              int varIndex = 0;
              for (int i = 0; i < columns.length; i++) {
                  if (!columns[i].equals(uniqueColumn) && values[i] != null) {
                      varIndex++;
                      if (numeric != null && numeric[i]) {
                          setNumeric(stmt, varIndex, columns[i], values[i]);
                      } else {
                          stmt.setString(varIndex, values[i]);
                      }
                  }
              }
              varIndex++;
              stmt
                      .setString(varIndex, getSelector(columns,
                                                       values,
                                                       uniqueColumn));
  
              // execute and return true if existing row was updated
              return stmt.executeUpdate() > 0;
  
          } finally {
              closeStatement(stmt);
          }
      }
docs: Updates an existing row.
  
  @return false if the row did not previously exist and therefore was not
  updated.