cloud-fan commented on a change in pull request #24246: [SPARK-24252][SQL] Add TableCatalog API URL: https://github.com/apache/spark/pull/24246#discussion_r277347568
########## File path: sql/catalyst/src/main/java/org/apache/spark/sql/catalog/v2/TableChange.java ########## @@ -0,0 +1,363 @@ +/* + * 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.catalog.v2; + +import org.apache.spark.sql.types.DataType; + +/** + * TableChange subclasses represent requested changes to a table. These are passed to + * {@link TableCatalog#alterTable}. For example, + * <pre> + * import TableChange._ + * val catalog = Catalogs.load(name) + * catalog.asTableCatalog.alterTable(ident, + * addColumn("x", IntegerType), + * renameColumn("a", "b"), + * deleteColumn("c") + * ) + * </pre> + */ +public interface TableChange { + + /** + * Create a TableChange for setting a table property. + * <p> + * If the property already exists, it will be replaced with the new value. + * + * @param property the property name + * @param value the new property value + * @return a TableChange for the addition + */ + static TableChange setProperty(String property, String value) { + return new SetProperty(property, value); + } + + /** + * Create a TableChange for removing a table property. + * <p> + * If the property does not exist, the change will succeed. + * + * @param property the property name + * @return a TableChange for the addition + */ + static TableChange removeProperty(String property) { + return new RemoveProperty(property); + } + + /** + * Create a TableChange for adding an optional column. + * <p> + * If the field already exists, the change will result in an {@link IllegalArgumentException}. + * If the new field is nested and its parent does not exist or is not a struct, the change will + * result in an {@link IllegalArgumentException}. + * + * @param fieldNames field names of the new column + * @param dataType the new column's data type + * @return a TableChange for the addition + */ + static TableChange addColumn(String[] fieldNames, DataType dataType) { Review comment: > We don't want to require callers to think about what missing values should be The caller is Spark, that's why I think it doesn't matter. The drawback of putting default value here is: we need to add several overloads. There are 3 `addColumn` methods here. We may need more overloads if we decide to add column properties. ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
