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https://issues.apache.org/jira/browse/FLINK-12820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16862843#comment-16862843
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Yun Tang commented on FLINK-12820:
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Would you please help to clarify why current solution is impossible when using
scala tuples or case classes?
> Support ignoring null fields when writing to Cassandra
> ------------------------------------------------------
>
> Key: FLINK-12820
> URL: https://issues.apache.org/jira/browse/FLINK-12820
> Project: Flink
> Issue Type: Improvement
> Components: Connectors / Cassandra
> Affects Versions: 1.8.0
> Reporter: Ozan Cicekci
> Priority: Minor
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Currently, records which have null fields are written to their corresponding
> columns in Cassandra as null. Writing null is basically a 'delete' for
> Cassandra, it's useful if nulls should correspond to deletes in the data
> model, but nulls can also indicate a missing data or partial column update.
> In that case, we end up overwriting columns of existing record on Cassandra
> with nulls.
>
> I believe it's already possible to ignore null values for POJO's with mapper
> options, as documented here:
> [https://ci.apache.org/projects/flink/flink-docs-stable/dev/connectors/cassandra.html#cassandra-sink-example-for-streaming-pojo-data-type]
>
> But this is not possible when using scala tuples or case classes. Perhaps
> with a Cassandra sink configuration flag, null values can be unset using
> below option for tuples and case classes.
> [https://docs.datastax.com/en/drivers/java/3.0/com/datastax/driver/core/BoundStatement.html#unset-int-]
>
> Here is the equivalent configuration in spark-cassandra-connector;
> [https://github.com/datastax/spark-cassandra-connector/blob/master/doc/5_saving.md#globally-treating-all-nulls-as-unset]
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