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https://issues.apache.org/jira/browse/FLINK-6442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16087343#comment-16087343
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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_r127456022
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/api/TableEnvironment.scala
---
@@ -488,19 +499,50 @@ abstract class TableEnvironment(val config:
TableConfig) {
* tEnv.sql(s"SELECT * FROM $table")
* }}}
*
- * @param query The SQL query to evaluate.
- * @return The result of the query as Table.
+ * @param sql The SQL string to evaluate.
+ * @return The result of the query as Table or null of the DML insert
operation.
*/
- def sql(query: String): Table = {
+ def sql(sql: String): Table = {
val planner = new FlinkPlannerImpl(getFrameworkConfig, getPlanner,
getTypeFactory)
// parse the sql query
- val parsed = planner.parse(query)
+ val parsed = planner.parse(sql)
// validate the sql query
val validated = planner.validate(parsed)
- // transform to a relational tree
- val relational = planner.rel(validated)
- new Table(this, LogicalRelNode(relational.rel))
+ // separate source translation if DML insert, considering sink
operation has no output but all
+ // RelNodes' translation should return a DataSet/DataStream, and
Calcite's TableModify
+ // defines output for DML(INSERT,DELETE,UPDATE) is a RowCount column
of BigInt type. This a
+ // work around since we have no conclusion for the output type
definition of sink operation
+ // (compare to traditional SQL insert).
+ if (parsed.isInstanceOf[SqlInsert]) {
+ val insert = parsed.asInstanceOf[SqlInsert]
+ // validate sink table
+ val targetName =
insert.getTargetTable.asInstanceOf[SqlIdentifier].names.get(0)
+ val targetTable = getTable(targetName)
+ if (null == targetTable ||
!targetTable.isInstanceOf[TableSinkTable[_]]) {
+ throw new TableException("SQL DML INSERT operation need a
registered TableSink Table!")
+ }
+ // validate unsupported partial insertion to sink table
+ val sinkTable = targetTable.asInstanceOf[TableSinkTable[_]]
+ if (null != insert.getTargetColumnList &&
insert.getTargetColumnList.size() !=
+ sinkTable.fieldTypes.length) {
+ throw new TableException(
+ "SQL DML INSERT do not support insert partial columns of the
target table due to table " +
+ "columns haven’t nullable property definition for now!")
+ }
+
+ writeToSink(
+ new Table(this, LogicalRelNode(planner.rel(insert.getSource).rel)),
+ sinkTable.tableSink,
+ QueryConfig.getQueryConfigFromTableEnv(this)
--- End diff --
This will return the default configuration. If we move `INSERT INTO`
queries into a special method (like `sqlInsert()`), the method could have an
additional `QueryConfig` parameter.
Otherwise, users won't be able to tweak the execution of a streaming query.
> 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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