mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-15 10:52:30 +00:00
35 lines
1009 B
C++
35 lines
1009 B
C++
#pragma once
|
|
|
|
#include <DataTypes/IDataTypeDummy.h>
|
|
|
|
|
|
namespace DB
|
|
{
|
|
|
|
/** Data type that cannot have any values.
|
|
* Used to represent NULL of unknown type as Nullable(Nothing),
|
|
* and possibly for empty array of unknown type as Array(Nothing).
|
|
*/
|
|
class DataTypeNothing final : public IDataTypeDummy
|
|
{
|
|
public:
|
|
static constexpr bool is_parametric = false;
|
|
|
|
const char * getFamilyName() const override { return "Nothing"; }
|
|
TypeIndex getTypeId() const override { return TypeIndex::Nothing; }
|
|
|
|
MutableColumnPtr createColumn() const override;
|
|
|
|
bool equals(const IDataType & rhs) const override;
|
|
|
|
bool isParametric() const override { return false; }
|
|
bool textCanContainOnlyValidUTF8() const override { return true; }
|
|
bool haveMaximumSizeOfValue() const override { return true; }
|
|
size_t getSizeOfValueInMemory() const override { return 0; }
|
|
bool canBeInsideNullable() const override { return true; }
|
|
|
|
SerializationPtr doGetDefaultSerialization() const override;
|
|
};
|
|
|
|
}
|