@Override
  public String getColumnUpdateStatementWhereColumnIsNull(String tableName, String setColumnName, String conditionColumnName){
    return "UPDATE " + tableName + " SET " + setColumnName + "=? WHERE " + conditionColumnName + " IS NULL";
  }
Generating update SQL statement for {@link DBAccessor#executePreparedUpdate}

@param tableName name of the table
@param setColumnName column name, value of which need to be set
@param conditionColumnName column name for the condition
@return
ambari-server/src/main/java/org/apache/ambari/server/orm/helpers/dbms/GenericDbmsHelper.java