| /** |
| * Copyright 2011-2015 Quickstep Technologies LLC. |
| * Copyright 2015 Pivotal Software, Inc. |
| * |
| * 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_SCALAR_HPP_ |
| #define QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_SCALAR_HPP_ |
| |
| #include <memory> |
| #include <unordered_map> |
| |
| #include "query_optimizer/expressions/Expression.hpp" |
| #include "query_optimizer/expressions/ExprId.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| |
| class CatalogAttribute; |
| class Scalar; |
| |
| namespace optimizer { |
| namespace expressions { |
| |
| /** \addtogroup OptimizerExpressions |
| * @{ |
| */ |
| |
| class Scalar; |
| typedef std::shared_ptr<const Scalar> ScalarPtr; |
| |
| /** |
| * @brief Scalar expression that returns a single value based on input values |
| * that are not across multiple rows in an input relation. |
| */ |
| class Scalar : public Expression { |
| public: |
| ~Scalar() override {} |
| |
| /** |
| * @brief Converts this expression to an expression for evaluation (in |
| * quickstep execution expressions system under /expressions) |
| * with each attribute reference being replaced by a CatalogAttribute |
| * reference provided in \p substitution_map. |
| * |
| * @param substitution_map Map from ExprId to CatalogAttribute for use in |
| * substituting CatalogAttribute for |
| * AttributeReference. |
| * @return Concretized expression for evaluation. |
| */ |
| virtual ::quickstep::Scalar* concretize( |
| const std::unordered_map<ExprId, const CatalogAttribute*>& substitution_map) |
| const = 0; |
| |
| protected: |
| Scalar() {} |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(Scalar); |
| }; |
| |
| /** @} */ |
| |
| } // namespace expressions |
| } // namespace optimizer |
| } // namespace quickstep |
| |
| #endif /* QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_SCALAR_HPP_ */ |