| /** |
| * Copyright 2016, Quickstep Research Group, Computer Sciences Department, |
| * University of Wisconsin—Madison. |
| * |
| * Licensed 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. |
| **/ |
| |
| #ifndef QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_SEARCHED_CASE_HPP_ |
| #define QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_SEARCHED_CASE_HPP_ |
| |
| #include <memory> |
| #include <string> |
| #include <unordered_map> |
| #include <vector> |
| |
| #include "expressions/scalar/Scalar.hpp" |
| #include "query_optimizer/OptimizerTree.hpp" |
| #include "query_optimizer/expressions/AttributeReference.hpp" |
| #include "query_optimizer/expressions/ExprId.hpp" |
| #include "query_optimizer/expressions/Expression.hpp" |
| #include "query_optimizer/expressions/ExpressionType.hpp" |
| #include "query_optimizer/expressions/Predicate.hpp" |
| #include "query_optimizer/expressions/Scalar.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| class CatalogAttribute; |
| class Type; |
| |
| namespace optimizer { |
| namespace expressions { |
| |
| /** \addtogroup OptimizerExpressions |
| * @{ |
| */ |
| |
| class SearchedCase; |
| typedef std::shared_ptr<const SearchedCase> SearchedCasePtr; |
| |
| /** |
| * @brief A searched CASE expression. It searches the first predicate in |
| * <condition_predicates_> that evaluates to true and returns the value |
| * of the expression in <conditional_result_expressions_> at the same |
| * position; if none of <condition_predicates_> evaluate to true, returns |
| * the value of <else_result_expression_> when <else_result_expression_> |
| * is not NULL, otherwise returns NULL. |
| */ |
| class SearchedCase : public Scalar { |
| public: |
| ExpressionType getExpressionType() const override { |
| return ExpressionType::kSearchedCase; |
| } |
| |
| std::string getName() const override { |
| return "SearchedCase"; |
| } |
| |
| const Type& getValueType() const override { |
| return value_type_; |
| } |
| |
| /** |
| * @return The vector of condition predicates. |
| */ |
| const std::vector<PredicatePtr>& condition_predicates() const { |
| return condition_predicates_; |
| } |
| |
| /** |
| * @return The vector of conditional result expressions. |
| */ |
| const std::vector<ScalarPtr>& conditional_result_expressions() const { |
| return conditional_result_expressions_; |
| } |
| |
| /** |
| * @return The ELSE result expression. |
| */ |
| const ScalarPtr& else_result_expression() const { |
| return else_result_expression_; |
| } |
| |
| bool isConstant() const override; |
| |
| std::vector<AttributeReferencePtr> getReferencedAttributes() const override; |
| |
| ExpressionPtr copyWithNewChildren( |
| const std::vector<ExpressionPtr> &new_children) const override; |
| |
| ::quickstep::Scalar* concretize( |
| const std::unordered_map<ExprId, const CatalogAttribute*>& substitution_map) const override; |
| |
| /** |
| * @brief Creates an immutable SearchedCase. |
| * |
| * @param condition_predicates A vector of condition predicates. |
| * @param conditional_result_expressions A vector of result expressions, one |
| * for each condition predicate. |
| * @param else_result_expression The optional ELSE expression. |
| * @param value_type The data type of this expression which should be the |
| * unified type of all result expressions. |
| * @return An immutable SimpleCase. |
| */ |
| static SearchedCasePtr Create(const std::vector<PredicatePtr> &condition_predicates, |
| const std::vector<ScalarPtr> &conditional_result_expressions, |
| const ScalarPtr &else_result_expression, |
| const Type &value_type) { |
| return SearchedCasePtr(new SearchedCase(condition_predicates, |
| conditional_result_expressions, |
| else_result_expression, |
| value_type)); |
| } |
| |
| protected: |
| void getFieldStringItems(std::vector<std::string> *inline_field_names, |
| std::vector<std::string> *inline_field_values, |
| std::vector<std::string> *non_container_child_field_names, |
| std::vector<OptimizerTreeBaseNodePtr> *non_container_child_fields, |
| std::vector<std::string> *container_child_field_names, |
| std::vector<std::vector<OptimizerTreeBaseNodePtr>> *container_child_fields) const override; |
| |
| private: |
| SearchedCase(const std::vector<PredicatePtr> &condition_predicates, |
| const std::vector<ScalarPtr> &conditional_result_expressions, |
| const ScalarPtr &else_result_expression, |
| const Type &value_type) |
| : condition_predicates_(condition_predicates), |
| conditional_result_expressions_(conditional_result_expressions), |
| else_result_expression_(else_result_expression), |
| value_type_(value_type) { |
| for (const PredicatePtr &condition_predicate : condition_predicates_) { |
| addChild(condition_predicate); |
| } |
| for (const ScalarPtr &conditional_result_expression : conditional_result_expressions_) { |
| addChild(conditional_result_expression); |
| } |
| if (else_result_expression_ != nullptr) { |
| addChild(else_result_expression_); |
| } |
| } |
| |
| std::vector<PredicatePtr> condition_predicates_; |
| std::vector<ScalarPtr> conditional_result_expressions_; |
| |
| // May be NULL. |
| ScalarPtr else_result_expression_; |
| |
| const Type &value_type_; |
| |
| DISALLOW_COPY_AND_ASSIGN(SearchedCase); |
| }; |
| |
| /** @} */ |
| |
| } // namespace expressions |
| } // namespace optimizer |
| } // namespace quickstep |
| |
| #endif /* QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_SEARCHED_CASE_HPP_ */ |