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https://issues.apache.org/jira/browse/CALCITE-4085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17143113#comment-17143113
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Dawid Wysakowicz commented on CALCITE-4085:
-------------------------------------------
I created a PR, but unfortunately I faced problems with {{JavaType}} because it
behaves very differently to other {{RelDataType}}.
There is couple of problems with them:
* tests in TableFunctionTest fail because the table function returns a nullable
{{JavaType}}. This in turn with a change that keeps the original nullability of
an aliased record changes the nested types.
* tests that operate on linq4j fail, because it mismatches what comes from the
{{JavaType}} stack and the RexNode. Take for example a class:
{code}
public static class Dependent {
public final int empid;
public final int deptno;
}
public static class Employee {
public final int empid;
public final int deptno;
public final Dependent dependent
}
// Java type returns JavaType(int), whereas going through the modified
RexBuilder the type // will be equal to JavaType(java.lang.Integer), because I
implemented a logic that fixes the // nullability. I think in this case it make
more sense to treat it as java.lang.Integer, because if // the Employee class
is null, the empid will also be null
SELECT t.dependent.empid from Employee;
{code}
I know I did not explain that too clearly, but I tried :(
Do you have any suggestion how could I fix it?
> Improve nullability support for fields of structured type
> ---------------------------------------------------------
>
> Key: CALCITE-4085
> URL: https://issues.apache.org/jira/browse/CALCITE-4085
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Dawid Wysakowicz
> Assignee: Dawid Wysakowicz
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> As discussed in
> https://lists.apache.org/thread.html/r602ac95fff23dd1ef974fb396df7be061ab861384ec42f5c57ce0bc2%40%3Cdev.calcite.apache.org%3E
> I would like to change the way a type of a field of a record is derived at
> couple of locations. This helps frameworks such as Apache Flink to build
> support for nullable records with not null fields.
> I suggest to change:
> * SqlDotOperator#deriveType
> * SqlItemOperator#inferReturnType
> * AliasNamespace#validateImpl
> * RexBuilder#makeFieldAccessInternal
> * SqlValidatorImpl.DeriveTypeVisitor#visit(SqlIdentifier)
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