dianfu commented on a change in pull request #7209: [FLINK-10977][table] Add UnBounded FlatAggregate operator to streaming Table API URL: https://github.com/apache/flink/pull/7209#discussion_r242014642
########## File path: flink-libraries/flink-table/src/main/java/org/apache/flink/table/sinks/UpsertStreamTableSink.java ########## @@ -0,0 +1,91 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.table.sinks; + +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.api.java.typeutils.TupleTypeInfo; +import org.apache.flink.streaming.api.datastream.DataStream; +import org.apache.flink.table.api.Table; +import org.apache.flink.table.api.TableException; +import org.apache.flink.table.api.Types; + +/** + * Defines an external {@link TableSink} to emit a streaming {@link Table} with insert, update, and + * delete changes. The {@link Table} must be have unique key fields (atomic or composite) or be + * append-only. + * + * <p>If the {@link Table} does not have a unique key and is not append-only, a + * {@link TableException} will be thrown. + * + * <p>The unique key of the table is configured by the {@code UpsertStreamTableSink#setKeyFields()} + * method. + * + * <p>The {@link Table} will be converted into a stream of upsert and delete messages which are + * encoded as {@link Tuple2}. The first field is a {@link Boolean} flag to indicate the message + * type. The second field holds the record of the requested type T. + * + * <p>A message with true {@link Boolean} field is an upsert message for the configured key. + * A message with false flag is a delete message for the configured key. + * + * <p>If the table is append-only, all messages will have a true flag and must be interpreted + * as insertions. + * + * @param <T> Type of records that this {@link TableSink} expects and supports. + */ +public interface UpsertStreamTableSink<T> extends StreamTableSink<Tuple2<Boolean, T>> { + + /** + * Configures the unique key fields of the {@link Table} to write. + * The method is called after {@code TableSink.configure()}. + * + * <p>The keys array might be empty, if the table consists of a single (updated) record. + * If the table does not have a key and is append-only, the keys attribute is null. + * + * @param keys the field names of the table's keys, an empty array if the table has a single + * row, and null if the table is append-only and has no key. + */ + void setKeyFields(String[] keys); + + /** + * Enforce output key fields. Users can use this method to enforce output key fields which + * may different from key fields of the query. Note: use it when you know what you are doing. Review comment: may different -> may be different ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
