huaxingao commented on code in PR #44119: URL: https://github.com/apache/spark/pull/44119#discussion_r1431953737
########## sql/core/src/main/scala/org/apache/spark/sql/MergeIntoWriter.scala: ########## @@ -0,0 +1,315 @@ +/* + * 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.spark.sql + +import org.apache.spark.SparkRuntimeException +import org.apache.spark.annotation.Experimental +import org.apache.spark.sql.catalyst.analysis.UnresolvedRelation +import org.apache.spark.sql.catalyst.expressions.Expression +import org.apache.spark.sql.catalyst.plans.logical.{Assignment, DeleteAction, InsertAction, InsertStarAction, MergeAction, MergeIntoTable, UpdateAction, UpdateStarAction} +import org.apache.spark.sql.functions.expr + +/** + * `MergeIntoWriter` provides methods to define and execute merge actions based + * on specified conditions. + * + * @tparam T the type of data in the Dataset. + * @param table the name of the target table for the merge operation. + * @param ds the source Dataset to merge into the target table. + * @param on the merge condition. + * + * @since 4.0.0 + */ +@Experimental +class MergeIntoWriter[T] private[sql] (table: String, ds: Dataset[T], on: Column) { + + private val df: DataFrame = ds.toDF() + + private val sparkSession = ds.sparkSession + + private val tableName = sparkSession.sessionState.sqlParser.parseMultipartIdentifier(table) + + private val logicalPlan = df.queryExecution.logical + + private[sql] var matchedActions: Seq[MergeAction] = Seq.empty[MergeAction] + private[sql] var notMatchedActions: Seq[MergeAction] = Seq.empty[MergeAction] + private[sql] var notMatchedBySourceActions: Seq[MergeAction] = Seq.empty[MergeAction] + + /** + * Initialize a `WhenMatched` action without any condition. + * + * This `WhenMatched` can be followed by one of the following merge actions: + * - `updateAll`: Update all the target table fields with source dataset fields. + * - `update(Map)`: Update all the target table records while changing only + * a subset of fields based on the provided assignment. + * - `delete`: Delete all the target table records. + * + * @return a new `WhenMatched` object. + */ + def whenMatched(): WhenMatched[T] = { + new WhenMatched[T](this, None) + } + + /** + * Initialize a `WhenMatched` action with a condition. + * + * This `WhenMatched` action will be executed if and only if the specified `condition` + * is satisfied. + * + * This `WhenMatched` can be followed by one of the following merge actions: + * - `updateAll`: Update all the target table fields with source dataset fields. + * - `update(Map)`: Update all the target table records while changing only + * a subset of fields based on the provided assignment. + * - `delete`: Delete all the target table records. + * + * @param condition a `Column` representing the condition to be evaluated for the action. + * @return a new `WhenMatched` object configured with the specified condition. + */ + def whenMatched(condition: Column): WhenMatched[T] = { + new WhenMatched[T](this, Some(condition.expr)) + } + + /** + * Initialize a `WhenNotMatched` action without any condition. + * + * This `WhenNotMatched` can be followed by one of the following merge actions: + * - `insertAll`: Insert all the target table with source dataset records. + * - `insert(Map)`: Insert all the target table records while changing only + * a subset of fields based on the provided assignment. + * + * @return a new `WhenNotMatched` object. + */ + def whenNotMatched(): WhenNotMatched[T] = { + new WhenNotMatched[T](this, None) + } + + /** + * Initialize a `WhenNotMatched` action with a condition. + * + * This `WhenNotMatched` action will be executed if and only if the specified `condition` + * is satisfied. + * + * This `WhenNotMatched` can be followed by one of the following merge actions: + * - `insertAll`: Insert all the target table with source dataset records. + * - `insert(Map)`: Insert all the target table records while changing only + * a subset of fields based on the provided assignment. + * + * @param condition a `Column` representing the condition to be evaluated for the action. + * @return a new `WhenNotMatched` object configured with the specified condition. + */ + def whenNotMatched(condition: Column): WhenNotMatched[T] = { + new WhenNotMatched[T](this, Some(condition.expr)) + } + + /** + * Initialize a `WhenNotMatchedBySource` action without any condition. + * + * This `WhenNotMatchedBySource` can be followed by one of the following merge actions: + * - `updateAll`: Update all the target table fields with source dataset fields. + * - `update(Map)`: Update all the target table records while changing only + * a subset of fields based on the provided assignment. + * - `delete`: Delete all the target table records. + * + * @return a new `WhenNotMatchedBySource` object. + */ + def whenNotMatchedBySource(): WhenNotMatchedBySource[T] = { + new WhenNotMatchedBySource[T](this, None) + } + + /** + * Initialize a `WhenNotMatchedBySource` action with a condition. + * + * This `WhenNotMatchedBySource` action will be executed if and only if the specified `condition` + * is satisfied. + * + * This `WhenNotMatchedBySource` can be followed by one of the following merge actions: + * - `updateAll`: Update all the target table fields with source dataset fields. + * - `update(Map)`: Update all the target table records while changing only + * a subset of fields based on the provided assignment. + * - `delete`: Delete all the target table records. + * + * @param condition a `Column` representing the condition to be evaluated for the action. + * @return a new `WhenNotMatchedBySource` object configured with the specified condition. + */ + def whenNotMatchedBySource(condition: Column): WhenNotMatchedBySource[T] = { + new WhenNotMatchedBySource[T](this, Some(condition.expr)) + } + + /** + * Executes the merge operation. + */ + def merge(): Unit = { + if (matchedActions.isEmpty && notMatchedActions.isEmpty && notMatchedBySourceActions.isEmpty) { + throw new SparkRuntimeException( + errorClass = "NO_MERGE_ACTION_SPECIFIED", + messageParameters = Map.empty) + } + + val merge = MergeIntoTable( + UnresolvedRelation(tableName), + logicalPlan, + on.expr, + matchedActions, + notMatchedActions, + notMatchedBySourceActions) + val qe = sparkSession.sessionState.executePlan(merge) + qe.assertCommandExecuted() + } +} + +/** + * A class for defining actions to be taken when matching rows in a DataFrame during + * a merge operation. + * + * @param mergeIntoWriter The MergeIntoWriter instance responsible for writing data to a + * target DataFrame. + * @param condition An optional condition Expression that specifies when the actions + * should be applied. + * If the condition is None, the actions will be applied to all matched + * rows. + * + * @tparam T The type of data in the MergeIntoWriter. + */ +case class WhenMatched[T] private[sql]( Review Comment: I want to keep `mergeIntoWriter` simple. I prefer to keep the current implementation if you don't mind. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
