ClickHouse/src/Functions/toColumnTypeName.cpp
Li Yin 4088c0a7f3 Automated function registration
Automated register all functions with below naming convention by
iterating through the symbols:
void DB::registerXXX(DB::FunctionFactory &)
2022-07-29 15:39:50 +08:00

64 lines
1.7 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypeString.h>
#include <Core/Field.h>
namespace DB
{
namespace
{
/// Returns name of IColumn instance.
class FunctionToColumnTypeName : public IFunction
{
public:
static constexpr auto name = "toColumnTypeName";
static FunctionPtr create(ContextPtr)
{
return std::make_shared<FunctionToColumnTypeName>();
}
String getName() const override
{
return name;
}
bool useDefaultImplementationForNulls() const override { return false; }
bool useDefaultImplementationForNothing() const override { return false; }
bool useDefaultImplementationForLowCardinalityColumns() const override { return false; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
size_t getNumberOfArguments() const override
{
return 1;
}
DataTypePtr getReturnTypeImpl(const DataTypes & /*arguments*/) const override
{
return std::make_shared<DataTypeString>();
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
{
return DataTypeString().createColumnConst(input_rows_count, arguments[0].column->getName());
}
ColumnPtr getConstantResultForNonConstArguments(const ColumnsWithTypeAndName & arguments, const DataTypePtr &) const override
{
return DataTypeString().createColumnConst(1, arguments[0].type->createColumn()->getName());
}
};
}
REGISTER_FUNCTION(ToColumnTypeName)
{
factory.registerFunction<FunctionToColumnTypeName>();
}
}