twalthr commented on a change in pull request #11692: [FLINK-16992][table-common] Add all ability interfaces for table sources and sinks URL: https://github.com/apache/flink/pull/11692#discussion_r410169346
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/connector/sink/abilities/SupportsPartitioning.java ########## @@ -0,0 +1,109 @@ +/* + * 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.connector.sink.abilities; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.table.connector.sink.DynamicTableSink; + +import java.util.Map; + +/** + * Enables to write partitioned data in a {@link DynamicTableSink}. + * + * <p>Partitions split the data stored in an external system into smaller portions that are identified + * by one or more string-based partition keys. A single partition is represented as a {@code Map < String, String >} + * which maps each partition key to a partition value. Partition keys and their order are defined by the + * catalog table. + * + * <p>For example, data can be partitioned by region and within a region partitioned by month. The order + * of the partition keys (in the example: first by region then by month) is defined by the catalog table. A + * list of partitions could be: + * <pre> + * List( + * ['region'='europe', 'month'='2020-01'], + * ['region'='europe', 'month'='2020-02'], + * ['region'='asia', 'month'='2020-01'], + * ['region'='asia', 'month'='2020-02'] + * ) + * </pre> + * + * <p>Given the following partitioned table: + * <pre>{@code + * CREATE TABLE t (a INT, b STRING, c DOUBLE, region STRING, month STRING) PARTITION BY (region, month); + * }</pre> + * + * <p>We can insert data into <i>static table partitions</i> using the {@code INSERT INTO ... PARTITION} syntax: + * <pre>{@code + * INSERT INTO t PARTITION (region='europe', month='2020-01') SELECT a, b, c FROM my_view; + * }</pre> + * + * <p>If all partition keys get a value assigned in the {@code PARTITION} clause, the operation is considered + * as an "insertion into a static partition". In the above example, the query result should be written + * into the static partition {@code region='europe', month='2020-01'} which will be passed by the planner + * into {@link #applyStaticPartition(Map)}. + * + * <p>Alternatively, we can insert data into <i>dynamic table partitions</i> using the SQL syntax: + * <pre>{@code + * INSERT INTO t PARTITION (region='europe') SELECT a, b, c, month FROM another_view; + * }</pre> + * + * <p>If only a subset of all partition keys (a prefix part) get a value assigned in the {@code PARTITION} + * clause, the operation is considered as an "insertion into a dynamic partition". In the above example, + * the static partition part is {@code region='europe'} which will be passed by the planner into + * {@link #applyStaticPartition(Map)}. The remaining values for partition keys should be obtained from Review comment: I think a user can still add records with `asia` value in a `europe` partition. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
