code: public Optional<ColumnDefinitionSegment> findColumnDefinitionFromMetaData(final String columnName, final ShardingTableMetaData shardingTableMetaData) {
          if (!shardingTableMetaData.containsTable(getTables().getSingleTableName())) {
              return Optional.absent();
          }
          for (ColumnMetaData each : shardingTableMetaData.get(getTables().getSingleTableName()).getColumns().values()) {
              if (columnName.equalsIgnoreCase(each.getColumnName())) {
                  return Optional.of(new ColumnDefinitionSegment(columnName, each.getDataType(), each.isPrimaryKey()));
              }
          }
          return Optional.absent();
      }
docs: Find column definition from meta data.
  
  @param columnName column name
  @param shardingTableMetaData sharding table meta data
  @return column definition