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From "Aljoscha Krettek (JIRA)" <j...@apache.org>
Subject [jira] [Reopened] (FLINK-6442) Extend TableAPI Support Sink Table Registration and ‘insert into’ Clause in SQL
Date Wed, 08 Nov 2017 14:41:00 GMT

     [ https://issues.apache.org/jira/browse/FLINK-6442?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Aljoscha Krettek reopened FLINK-6442:
-------------------------------------

Reopen to fix release note.

> Extend TableAPI Support Sink Table Registration and ‘insert into’ Clause in SQL
> -------------------------------------------------------------------------------
>
>                 Key: FLINK-6442
>                 URL: https://issues.apache.org/jira/browse/FLINK-6442
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>            Reporter: lincoln.lee
>            Assignee: lincoln.lee
>            Priority: Minor
>             Fix For: 1.4.0
>
>
> Currently in TableAPI  there’s only registration method for source table,  when we
use SQL writing a streaming job, we should add additional part for the sink, like TableAPI
does:
> {code}
> val sqlQuery = "SELECT * FROM MyTable WHERE _1 = 3"
> val t = StreamTestData.getSmall3TupleDataStream(env)
> tEnv.registerDataStream("MyTable", t)
> // one way: invoke tableAPI’s writeToSink method directly
> val result = tEnv.sql(sqlQuery)
> result.writeToSink(new YourStreamSink)
> // another way: convert to datastream first and then invoke addSink 
> val result = tEnv.sql(sqlQuery).toDataStream[Row]
> result.addSink(new StreamITCase.StringSink)
> {code}
> From the api we can see the sink table always be a derived table because its 'schema'
is inferred from the result type of upstream query.
> Compare to traditional RDBMS which support DML syntax, a query with a target output could
be written like this:
> {code}
> insert into table target_table_name
> [(column_name [ ,...n ])]
> query
> {code}
> The equivalent form of the example above is as follows:
> {code}
>     tEnv.registerTableSink("targetTable", new YourSink)
>     val sql = "INSERT INTO targetTable SELECT a, b, c FROM sourceTable"
>     val result = tEnv.sql(sql)
> {code}
> It is supported by Calcite’s grammar: 
> {code}
>  insert:( INSERT | UPSERT ) INTO tablePrimary
>  [ '(' column [, column ]* ')' ]
>  query
> {code}
> I'd like to extend Flink TableAPI to support such feature.  see design doc: https://goo.gl/n3phK5



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