[jira] [Created] (BEAM-3157) BeamSql transform should support other PCollection types

["Ismaël Mejía (JIRA)" <ji...@apache.org>]

Ismaël Mejía created BEAM-3157:
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             Summary: BeamSql transform should support other PCollection types
                 Key: BEAM-3157
                 URL: https://issues.apache.org/jira/browse/BEAM-3157
             Project: Beam
          Issue Type: Improvement
          Components: dsl-sql
            Reporter: Ismaël Mejía


Currently the Beam SQL transform only supports input and output data represented as a BeamRecord. This seems to me like an usability limitation (even if we can do a ParDo to prepare objects before and after the transform).

I suppose this constraint comes from the fact that we need to map name/type/value from an object field into Calcite so it is convenient to have a specific data type (BeamRecord) for this. However we can accomplish the same by using a PCollection of JavaBean (where we know the same information via the field names/types/values) or by using Avro records where we also have the Schema information. For the output PCollection we can map the object via a Reference (e.g. a JavaBean to be filled with the names of an Avro object).

Note: I am assuming for the moment simple mappings since the SQL does not support composite types for the moment.

A simple API idea would be something like this:

PCollection<MyPojo> col = ...
PCollection<>BeamSql.query("SELECT ...", MyNewPojo.class);

A first approach could be to just add the extra ParDos + transform DoFns however I suppose that for memory use reasons maybe mapping directly into Calcite would make sense.




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