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https://issues.apache.org/jira/browse/FLINK-6442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16170673#comment-16170673
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ASF GitHub Bot commented on FLINK-6442:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/3829#discussion_r139466642
--- Diff: docs/dev/table/common.md ---
@@ -236,6 +236,52 @@ tableEnv.registerTableSource("CsvTable", csvSource)
{% top %}
+### Register a TableSink
+
+A `TableSink` [emits a Table](common.html#emit-a-table) to an external
storage system, such as a database, key-value store, message queue, or file
system (in different encodings, e.g., CSV, Parquet, or ORC).
+
+Flink aims to provide TableSources for common data formats and storage
systems. Please see the documentation about [Table Sources and Sinks]({{
site.baseurl }}/dev/table/sourceSinks.html) page for details about available
sinks and instructions for how to implement a custom `TableSink`.
+
+A `TableSink` is registered in a `TableEnvironment` as follows:
--- End diff --
We should add a short paragraph why Table, TableSource, and TableSink need
to be registered to the `Register a Table in the Catalog` section. The
subsection should have links to the sections that show how registered tables
are used (SQL: `FROM`, `INSERT INTO`, Table API: `scan()`, `insertInto()`).
> 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
>
> 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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