code: public boolean isShardingColumn(final String columnName, final String tableName) {
          for (TableRule each : tableRules) {
              if (each.getLogicTable().equalsIgnoreCase(tableName) && isShardingColumn(each, columnName)) {
                  return true;
              }
          }
          return false;
      }
docs: Judge is sharding column or not.
  
  @param columnName column name
  @param tableName table name
  @return is sharding column or not