Re: Question tableEnv.toDataSet : Table to DataSet<Tuple2<String,Integer>>

Posted by Camelia Elena Ciolac on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Question-tableEnv-toDataSet-Table-to-DataSet-Tuple2-String-Integer-tp8592p8594.html

Indeed, my source code was overall correct (thank you  Suneel Marthi  for confirming), but the COUNT function in Table SQL returns Long, not Integer.

So the working code is :

TypeInformation<Tuple2<String, Long>> typeInformation = TypeInformation.of(new TypeHint<Tuple2<String, Long>>() { });

DataSet<Tuple2<String, Long>> resDS = tableEnv.toDataSet(result, typeInformation);

Regards,

Camelia

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From: Camelia Elena Ciolac
Sent: Saturday, August 20, 2016 9:37 PM
To: [hidden email]
Subject: Question tableEnv.toDataSet : Table to DataSet<Tuple2<String,Integer>>

 

Good evening,

I started working with the beta Flink SQL in BatchTableEnvironment and I am interested to convert the resulted Table object into a DataSet<Tuple2<String,Integer>>.

I give some lines of code as example:

DataSet<Tuple4<String,String,Double,Double>> ds1 = ...

tableEnv.registerDataSet("EventsTable", ds1, "event_id,region,latitude,longitude");            

Table result = tableEnv.sql("SELECT region, COUNT(event_id) AS counter FROM EventsTable GROUP BY region");

TypeInformation<Tuple2<String, Integer>> typeInformation = TypeInformation.of(new TypeHint<Tuple2<String, Integer>>() { });

DataSet<Tuple2<String, Integer>> resDS = tableEnv.toDataSet(result, typeInformation);

            

At runtime, I get error:

Caused by: org.apache.flink.api.table.codegen.CodeGenException: Incompatible types of expression and result type.

at org.apache.flink.api.table.codegen.CodeGenerator$$anonfun$generateResultExpression$2.apply(CodeGenerator.scala:327)

at org.apache.flink.api.table.codegen.CodeGenerator$$anonfun$generateResultExpression$2.apply(CodeGenerator.scala:325)

at scala.collection.Iterator$class.foreach(Iterator.scala:727)

at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)

at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)

at scala.collection.AbstractIterable.foreach(Iterable.scala:54)

at org.apache.flink.api.table.codegen.CodeGenerator.generateResultExpression(CodeGenerator.scala:325)

at org.apache.flink.api.table.codegen.CodeGenerator.generateConverterResultExpression(CodeGenerator.scala:269)

at org.apache.flink.api.table.plan.nodes.dataset.DataSetRel$class.getConversionMapper(DataSetRel.scala:89)

at org.apache.flink.api.table.plan.nodes.dataset.DataSetAggregate.getConversionMapper(DataSetAggregate.scala:38)

at org.apache.flink.api.table.plan.nodes.dataset.DataSetAggregate.translateToPlan(DataSetAggregate.scala:142)

at org.apache.flink.api.table.BatchTableEnvironment.translate(BatchTableEnvironment.scala:274)

at org.apache.flink.api.java.table.BatchTableEnvironment.toDataSet(BatchTableEnvironment.scala:163)

What is the correct way to achieve this ?

According to solved JIRA issue FLINK-1991 (https://issues.apache.org/jira/browse/FLINK-1991) , this is now possible (in Flink 1.1.0). 

As a side note, it works transforming to DataSet<Row>, but when trying to convert to a POJO dataset (again with fields String region and Integer counter) it gives the same error as above.

Thanks in advance,

Best regards,

Camelia