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From "sunjincheng (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-5695) Optimize table type systems based on database semantics
Date Fri, 03 Feb 2017 02:43:52 GMT

    [ https://issues.apache.org/jira/browse/FLINK-5695?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15850965#comment-15850965
] 

sunjincheng commented on FLINK-5695:
------------------------------------

Hi, [~fhueske] , Yes, I would like to explain my purpose:
       There are only one "select" operation for WindowGroupedTable. GroupedTable also has
only one "select" operation, and all of them are generated by "groupBy" operation (WindowedTable.groupBy
| Table.groupBy). The only difference is groupBy's keys, The keys of "WindowedTable" "GroupBy"
operation contain the "window", for the user is just add window-related fields in the table,
such as windowStrat and windowEnd. "GroupedTable.select" and "WindowGroupedTable.select" semantics
is no different, GroupedTable type easy to understand by users, and  "GroupedTable" should
have all of the characteristics which "WindowGroupedTable" have, so I personally feel should
be removed "WindowGroupedTable" type.

> Optimize table type systems based on database semantics
> -------------------------------------------------------
>
>                 Key: FLINK-5695
>                 URL: https://issues.apache.org/jira/browse/FLINK-5695
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: sunjincheng
>            Assignee: sunjincheng
>
> Optimize table type systems based on database semantics.As follows:
> {code}
>              groupBy
>          -------------------->
> Table                             GroupedTable
>   ∧   <--------------------           ∧
>    |         select&agg                |
>    |                                           |
>    | where                                |
>    | select                                | groupBy
>    | agg                                   |
>    | ...                                      |
>    |             window                 |
>   ∨     --------------------->     
>  Table                            WindowedTable
>           <---------------------
>               select&over
> {code}
> What do you think? [~fhueske] 



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