[
https://issues.apache.org/jira/browse/FLINK-5698?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15855634#comment-15855634
]
ASF GitHub Bot commented on FLINK-5698:
---------------------------------------
Github user wuchong commented on the issue:
https://github.com/apache/flink/pull/3269
Hi @tonycox , thanks for this PR.
It seems that you are using column names to represent the (nested) fields
that are projected. I'm afraid that it can't work when the composite columns
have the same nested field name. Such as a table schema `student<name, age>,
teacher<name, age>`, and the projected fields are `name, age`, we can't
determine whether the `name` is `student.name` or `teacher.name`.
IMO, we can use the full qualifier column names with `.` separator to
represent the (nested) fields. For the above example, the projected fields
could be `student.name, teacher.age`. And then we can use it to do nested field
projection push down.
What do you think ?
Thanks,
Jark Wu
> Add NestedFieldsProjectableTableSource interface
> ------------------------------------------------
>
> Key: FLINK-5698
> URL: https://issues.apache.org/jira/browse/FLINK-5698
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Anton Solovev
> Assignee: Anton Solovev
>
> Add a NestedFieldsProjectableTableSource interface for some TableSource
> implementation that support nesting projection push-down.
> The interface could look as follows
> {code}
> def trait NestedFieldsProjectableTableSource {
> def projectNestedFields(fields: Array[String]):
> NestedFieldsProjectableTableSource[T]
> }
> {code}
> This interface works together with ProjectableTableSource
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
