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56 lines
1.4 KiB
C++
56 lines
1.4 KiB
C++
#include <Functions/IFunctionImpl.h>
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#include <Functions/FunctionFactory.h>
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#include <Interpreters/Context.h>
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#include <DataTypes/DataTypeString.h>
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#include <Core/Field.h>
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namespace DB
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{
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class FunctionCurrentDatabase : public IFunction
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{
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const String db_name;
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public:
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static constexpr auto name = "currentDatabase";
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static FunctionPtr create(const Context & context)
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{
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return std::make_shared<FunctionCurrentDatabase>(context.getCurrentDatabase());
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}
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explicit FunctionCurrentDatabase(const String & db_name_) : db_name{db_name_}
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{
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}
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String getName() const override
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{
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return name;
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}
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size_t getNumberOfArguments() const override
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{
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return 0;
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}
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DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
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{
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return std::make_shared<DataTypeString>();
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}
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bool isDeterministic() const override { return false; }
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void executeImpl(Block & block, const ColumnNumbers &, size_t result, size_t input_rows_count) const override
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{
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block.getByPosition(result).column = DataTypeString().createColumnConst(input_rows_count, db_name);
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}
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};
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void registerFunctionCurrentDatabase(FunctionFactory & factory)
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{
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factory.registerFunction<FunctionCurrentDatabase>();
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factory.registerFunction<FunctionCurrentDatabase>("DATABASE", FunctionFactory::CaseInsensitive);
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}
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}
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