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https://issues.apache.org/jira/browse/CALCITE-6579?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17886464#comment-17886464
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Mihai Budiu commented on CALCITE-6579:
--------------------------------------
Technically CREATE TABLE is part of server (not Calcite core), so you can
actually use your own implementation of server and tweak how the CREATE TABLE
statement is interpreted, and create types with proper nullability.
> Unexpected nullable checks for nullable types with non-nullable children
> -------------------------------------------------------------------------
>
> Key: CALCITE-6579
> URL: https://issues.apache.org/jira/browse/CALCITE-6579
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.37.0
> Reporter: david radley
> Priority: Major
>
> This Jira is raised for the issue discussed in
> [https://lists.apache.org/thread/x857njnd42gcvrldbcd7y85to6fb58dn]
>
> I am using flink and have a table definition like this.
> _CREATE TABLE source_1 ( `order_id` STRING NOT NULL, `order_time` STRING NOT
> NULL, `buyer` ROW< `first_name` STRING, `last_name` STRING NOT NULL, `title`
> STRING NOT NULL_
> _) WITH ( 'connector' = 'kafka', 'topic' = 'mytopic',
> 'properties.bootstrap.servers' = 'localhost:9092', 'value.format' = 'avro',
> 'value.fields-include' = 'ALL', 'scan.startup.mode' = 'earliest-offset' );_
>
> This errors as code in Calcite does not create the correct schema.
> It sets`last_name` STRING NOT NULL, `title` STRING NOT NULL to both be
> nullable.
> The cause of this is in the table planner when we convert SqlDataTypeSpec to
> the RelDataType. We push the nullable of buyer onto all of its fields, losing
> the children’s nullable status . In the debugger I see that it is taking the
> nullable true (from buyer) and putting this on all the children in
> [fixupNullability|http://example.com]https://github.com/davidradl/calcite/blob/ad2e843c5d9b3bec001d22e680ebe6b5de4e2078/core/src/main/java/org/apache/calcite/sql/SqlDataTypeSpec.java#L238.
> I can see that the SqlDataTypeSpec has this information but it is not used.
>
> Flink maps this directly to an Avro schema that incorreclty polices the Avro
> payload.
>
> In terms of fixing this, I wonder if the type could be created with the
> correct nullable so it doesn’t need to be fixed up or whether we should pass
> down the SqlDataTypeSpec so it has the right information to set the nullable
> status.
>
> This subject has previously been raised on the dev list
> [https://lists.apache.org/thread/s4nd9rk0fzckoctokl7kjdbtfbvxncy7] by
> [~dwysakowicz]
>
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