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Posted to issues@flink.apache.org by "ASF GitHub Bot (Jira)" <ji...@apache.org> on 2021/06/01 00:59:00 UTC
[jira] [Updated] (FLINK-22689) Table API Documentation Row-Based
Operations Example Fails
[ https://issues.apache.org/jira/browse/FLINK-22689?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
ASF GitHub Bot updated FLINK-22689:
-----------------------------------
Labels: pull-request-available (was: )
> Table API Documentation Row-Based Operations Example Fails
> ----------------------------------------------------------
>
> Key: FLINK-22689
> URL: https://issues.apache.org/jira/browse/FLINK-22689
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / API
> Affects Versions: 1.12.1
> Reporter: Yunfeng Zhou
> Assignee: Yao Zhang
> Priority: Major
> Labels: pull-request-available
>
> I wrote the following program according to the example code provided in [Documentation/Table API/Row-based operations|https://ci.apache.org/projects/flink/flink-docs-release-1.13/docs/dev/table/tableapi/#row-based-operations]
> {code:java}
> public class TableUDF {
> public static void main(String[] args) {
> StreamExecutionEnvironment env = StreamExecutionEnvironment.createLocalEnvironment();
> StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);
>
> Table input = tEnv.fromValues(
> DataTypes.of("ROW<c STRING>"),
> Row.of("name")
> );
>
> ScalarFunction func = new MyMapFunction();
> tEnv.registerFunction("func", func);
>
> Table table = input
> .map(call("func", $("c")).as("a", "b")); // exception occurs here
>
> table.execute().print();
> }
>
> public static class MyMapFunction extends ScalarFunction {
> public Row eval(String a) {
> return Row.of(a, "pre-" + a);
> }
>
> @Override
> public TypeInformation<?> getResultType(Class<?>[] signature) {
> return Types.ROW(Types.STRING, Types.STRING);
> }
> }
> }
> {code}
> The code above would throw an exception like this:
> {code}
> Exception in thread "main" org.apache.flink.table.api.ValidationException: Only a scalar function can be used in the map operator.
> at org.apache.flink.table.operations.utils.OperationTreeBuilder.map(OperationTreeBuilder.java:480)
> at org.apache.flink.table.api.internal.TableImpl.map(TableImpl.java:519)
> at org.apache.flink.ml.common.function.TableUDFBug.main(TableUDF.java:29)
> {code}
> The core of the program above is identical to that provided in flink documentation, but it cannot function correctly. This might affect users who want to use custom function with table API.
>
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