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_r276185183
########## File path: sql/catalyst/src/main/java/org/apache/spark/sql/catalog/v2/TableChange.java ########## @@ -0,0 +1,293 @@ +/* + * 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. + * + * @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. + * + * @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 to a table. + * + * @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) { + return new AddColumn(fieldNames, dataType, true, null); + } + + /** + * Create a TableChange for adding a column to a table. + * + * @param fieldNames field names of the new column + * @param dataType the new column's data type + * @param isNullable whether the new column can contain null + * @return a TableChange for the addition + */ + static TableChange addColumn(String[] fieldNames, DataType dataType, boolean isNullable) { + return new AddColumn(fieldNames, dataType, isNullable, null); + } + + /** + * Create a TableChange for adding a top-level column to a table. + * + * @param fieldNames field names of the new column + * @param dataType the new column's data type + * @param isNullable whether the new column can contain null + * @param comment the new field's comment string + * @return a TableChange for the addition + */ + static TableChange addColumn( + String[] fieldNames, + DataType dataType, + boolean isNullable, + String comment) { + return new AddColumn(fieldNames, dataType, isNullable, comment); + } + + /** + * Create a TableChange for renaming a field. + * <p> + * The name is used to find the field to rename. The new name will replace the leaf field name. + * For example, renameColumn("a.b.c", "x") should produce column a.b.x. + * + * @param fieldNames the current field names + * @param newName the new name + * @return a TableChange for the rename + */ + static TableChange renameColumn(String[] fieldNames, String newName) { + return new RenameColumn(fieldNames, newName); + } + + /** + * Create a TableChange for updating the type of a field. + * <p> + * The field names are used to find the field to update. + * + * @param fieldNames field names of the column to update + * @param newDataType the new data type + * @return a TableChange for the update + */ + static TableChange updateColumn(String[] fieldNames, DataType newDataType) { + return new UpdateColumn(fieldNames, newDataType, true); + } + + /** + * Create a TableChange for updating the type of a field. + * <p> + * The field names are used to find the field to update. + * + * @param fieldNames field names of the column to update + * @param newDataType the new data type + * @return a TableChange for the update + */ + static TableChange updateColumn(String[] fieldNames, DataType newDataType, boolean isNullable) { Review comment: I think it's better for UX, but we will have too many overloads. How about we create a class `ColumnBuilder`? ``` case class Column(nameParts: Array[String], dt: DataType, nullable: Boolean, comment: Option[String]) class ColumnBuilder { def withName(name: String) def withNameParts(nameParts: String) def withNullable(nullable: Boolean) ... } ``` And in `TableChange` we just need to declare `Column` in the methods. ---------------------------------------------------------------- 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]
