org.apache.storm.jdbc.mapper

## Interface JdbcLookupMapper

- All Superinterfaces:
    JdbcMapper, Serializable
  All Known Implementing Classes:
    SimpleJdbcLookupMapper

      public interface JdbcLookupMapper
      extends JdbcMapper

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `declareOutputFields(OutputFieldsDeclarer declarer)` declare what are the fields that this code will output.
    `List<Values>` | `toTuple(ITuple input, List<Column> columns)` Converts a DB row to a list of storm values that can be emitted.

    - ### Methods inherited from interface org.apache.storm.jdbc.mapper.JdbcMapper

      `getColumns`

- - ### Method Detail

    - #### toTuple

          List<Values> toTuple(ITuple input,
                               List<Column> columns)

      Converts a DB row to a list of storm values that can be emitted. This is done to allow a single storm input tuple and a single DB row to result in multiple output values.

      Parameters:
        `input` - the input tuple.
        `columns` - list of columns that represents a row
      Returns:
        a List of storm values that can be emitted. Each item in list is emitted as an output tuple.

    - #### declareOutputFields

          void declareOutputFields(OutputFieldsDeclarer declarer)

      declare what are the fields that this code will output.

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