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ASF GitHub Bot commented on DRILL-6768: --------------------------------------- KazydubB commented on a change in pull request #1494: DRILL-6768: Improve to_date, to_time and to_timestamp and correspondi… URL: https://github.com/apache/drill/pull/1494#discussion_r224023529 ########## File path: logical/src/main/java/org/apache/drill/common/expression/fn/ToFunctions.java ########## @@ -0,0 +1,130 @@ +/* + * 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.drill.common.expression.fn; + +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; + +import org.apache.drill.common.types.TypeProtos.DataMode; +import org.apache.drill.common.types.TypeProtos.MinorType; + +public class ToFunctions { + + private static Map<MinorType, String> TO_FUNC = new HashMap<>(); + /** The to functions that need to be replaced (if + * "drill.exec.functions.cast_empty_string_to_null" is set to true). */ + private static Set<String> TO_FUNC_REPLACEMENT_NEEDED = new HashSet<>(); + /** Map from the replaced functions to the new ones (for non-nullable VARCHAR). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NONNULLABLE_VARCHAR = new HashMap<>(); + /** Map from the replaced functions to the new ones (for non-nullable VAR16CHAR). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NONNULLABLE_VAR16CHAR = new HashMap<>(); + /** Map from the replaced functions to the new ones (for non-nullable VARBINARY). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NONNULLABLE_VARBINARY = new HashMap<>(); + /** Map from the replaced functions to the new ones (for nullable VARCHAR). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NULLABLE_VARCHAR = new HashMap<>(); + /** Map from the replaced functions to the new ones (for nullable VAR16CHAR). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NULLABLE_VAR16CHAR = new HashMap<>(); + /** Map from the replaced functions to the new ones (for nullable VARBINARY). */ + private static Map<String, String> FUNC_REPLACEMENT_FROM_NULLABLE_VARBINARY = new HashMap<>(); + + static { + TO_FUNC.put(MinorType.DATE, "to_date"); + TO_FUNC.put(MinorType.TIME, "to_time"); + TO_FUNC.put(MinorType.TIMESTAMP, "to_timestamp"); + + setupReplacementFunctions(MinorType.DATE, "NullableDate"); + setupReplacementFunctions(MinorType.TIME, "NullableTime"); + setupReplacementFunctions(MinorType.TIMESTAMP, "NullableTimeStamp"); + } + + private static void setupReplacementFunctions(MinorType type, String toType) { + String functionName = TO_FUNC.get(type); + + TO_FUNC_REPLACEMENT_NEEDED.add(functionName); + + FUNC_REPLACEMENT_FROM_NONNULLABLE_VARCHAR.put(functionName, "convertVarCharTo" + toType); + FUNC_REPLACEMENT_FROM_NONNULLABLE_VAR16CHAR.put(functionName, "convertVar16CharTo" + toType); + FUNC_REPLACEMENT_FROM_NONNULLABLE_VARBINARY.put(functionName, "convertVarBinaryTo" + toType); + FUNC_REPLACEMENT_FROM_NULLABLE_VARCHAR.put(functionName, "convertNullableVarCharTo" + toType); + FUNC_REPLACEMENT_FROM_NULLABLE_VAR16CHAR.put(functionName, "convertNullableVar16CharTo" + toType); + FUNC_REPLACEMENT_FROM_NULLABLE_VARBINARY.put(functionName, "convertNullableVarBinaryTo" + toType); + } + + /** + * Get a replacing to_ function for the original function, based on the specified data mode. Should be used + * iff {@link #isReplacementNeeded(String, MinorType)} returns {@code true}. Review comment: OK, it seems this shortening is not well-known. Changing it to a more verbose one. ---------------------------------------------------------------- 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: us...@infra.apache.org > Improve to_date, to_time and to_timestamp and corresponding cast functions to > handle empty string when `drill.exec.functions.cast_empty_string_to_null` > option is enabled > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- > > Key: DRILL-6768 > URL: https://issues.apache.org/jira/browse/DRILL-6768 > Project: Apache Drill > Issue Type: Improvement > Affects Versions: 1.14.0 > Reporter: Bohdan Kazydub > Assignee: Bohdan Kazydub > Priority: Major > Labels: doc-impacting > Fix For: 1.15.0 > > > When `drill.exec.functions.cast_empty_string_to_null` option is enabled > `to_date`, `to_time` and `to_timestamp` functions while converting string to > according type in case if null or empty string values are passed will return > NULL (to avoid CASE clauses which are littering a query and will work in > accordance with their respective CAST counterparts) for both cases. > > > > CASTs will be handled in a similar way (uniformly with numeric types): > > ||Value to cast||Now||Will be|| > |NULL|NULL|NULL| > |'' (empty string)|Error in many cases (except numerical types)|NULL| > CAST empty string to null (in case of enabled option) will be supported by > DATE, TIME, TIMESTAMP, INTERVAL YEAR, INTERVAL MONTH and INTERVAL DAY > functions in addition to numeric types. > > *For documentation* > TBA -- This message was sent by Atlassian JIRA (v7.6.3#76005)