1 | #pragma once |
2 | |
3 | #include <DataTypes/IDataType.h> |
4 | |
5 | namespace DB |
6 | { |
7 | |
8 | /// A nullable data type is an ordinary data type provided with a tag |
9 | /// indicating that it also contains the NULL value. The following class |
10 | /// embodies this concept. |
11 | class DataTypeNullable final : public IDataType |
12 | { |
13 | public: |
14 | static constexpr bool is_parametric = true; |
15 | |
16 | explicit DataTypeNullable(const DataTypePtr & nested_data_type_); |
17 | std::string doGetName() const override { return "Nullable(" + nested_data_type->getName() + ")" ; } |
18 | const char * getFamilyName() const override { return "Nullable" ; } |
19 | TypeIndex getTypeId() const override { return TypeIndex::Nullable; } |
20 | |
21 | void enumerateStreams(const StreamCallback & callback, SubstreamPath & path) const override; |
22 | |
23 | void serializeBinaryBulkStatePrefix( |
24 | SerializeBinaryBulkSettings & settings, |
25 | SerializeBinaryBulkStatePtr & state) const override; |
26 | |
27 | void serializeBinaryBulkStateSuffix( |
28 | SerializeBinaryBulkSettings & settings, |
29 | SerializeBinaryBulkStatePtr & state) const override; |
30 | |
31 | void deserializeBinaryBulkStatePrefix( |
32 | DeserializeBinaryBulkSettings & settings, |
33 | DeserializeBinaryBulkStatePtr & state) const override; |
34 | |
35 | void serializeBinaryBulkWithMultipleStreams( |
36 | const IColumn & column, |
37 | size_t offset, |
38 | size_t limit, |
39 | SerializeBinaryBulkSettings & settings, |
40 | SerializeBinaryBulkStatePtr & state) const override; |
41 | |
42 | void deserializeBinaryBulkWithMultipleStreams( |
43 | IColumn & column, |
44 | size_t limit, |
45 | DeserializeBinaryBulkSettings & settings, |
46 | DeserializeBinaryBulkStatePtr & state) const override; |
47 | |
48 | void serializeBinary(const Field & field, WriteBuffer & ostr) const override; |
49 | void deserializeBinary(Field & field, ReadBuffer & istr) const override; |
50 | void serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override; |
51 | void deserializeBinary(IColumn & column, ReadBuffer & istr) const override; |
52 | void serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
53 | void deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override; |
54 | void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
55 | void deserializeTextQuoted(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override; |
56 | void deserializeWholeText(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override; |
57 | |
58 | void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
59 | |
60 | /** It is questionable, how NULL values could be represented in CSV. There are three variants: |
61 | * 1. \N |
62 | * 2. empty string (without quotes) |
63 | * 3. NULL |
64 | * We support all of them (however, second variant is supported by CSVRowInputStream, not by deserializeTextCSV). |
65 | * (see also input_format_defaults_for_omitted_fields and input_format_csv_unquoted_null_literal_as_null settings) |
66 | * In CSV, non-NULL string value, starting with \N characters, must be placed in quotes, to avoid ambiguity. |
67 | */ |
68 | void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings & settings) const override; |
69 | |
70 | void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
71 | void deserializeTextJSON(IColumn & column, ReadBuffer & istr, const FormatSettings &) const override; |
72 | void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
73 | void serializeTextXML(const IColumn & column, size_t row_num, WriteBuffer & ostr, const FormatSettings &) const override; |
74 | |
75 | void serializeProtobuf(const IColumn & column, size_t row_num, ProtobufWriter & protobuf, size_t & value_index) const override; |
76 | void deserializeProtobuf(IColumn & column, ProtobufReader & protobuf, bool allow_add_row, bool & row_added) const override; |
77 | |
78 | MutableColumnPtr createColumn() const override; |
79 | |
80 | Field getDefault() const override; |
81 | |
82 | bool equals(const IDataType & rhs) const override; |
83 | |
84 | bool isParametric() const override { return true; } |
85 | bool haveSubtypes() const override { return true; } |
86 | bool cannotBeStoredInTables() const override { return nested_data_type->cannotBeStoredInTables(); } |
87 | bool shouldAlignRightInPrettyFormats() const override { return nested_data_type->shouldAlignRightInPrettyFormats(); } |
88 | bool textCanContainOnlyValidUTF8() const override { return nested_data_type->textCanContainOnlyValidUTF8(); } |
89 | bool isComparable() const override { return nested_data_type->isComparable(); } |
90 | bool canBeComparedWithCollation() const override { return nested_data_type->canBeComparedWithCollation(); } |
91 | bool canBeUsedAsVersion() const override { return false; } |
92 | bool isSummable() const override { return nested_data_type->isSummable(); } |
93 | bool canBeUsedInBooleanContext() const override { return nested_data_type->canBeUsedInBooleanContext(); } |
94 | bool haveMaximumSizeOfValue() const override { return nested_data_type->haveMaximumSizeOfValue(); } |
95 | size_t getMaximumSizeOfValueInMemory() const override { return 1 + nested_data_type->getMaximumSizeOfValueInMemory(); } |
96 | bool isNullable() const override { return true; } |
97 | size_t getSizeOfValueInMemory() const override; |
98 | bool onlyNull() const override; |
99 | bool canBeInsideLowCardinality() const override { return nested_data_type->canBeInsideLowCardinality(); } |
100 | |
101 | const DataTypePtr & getNestedType() const { return nested_data_type; } |
102 | |
103 | /// If ReturnType is bool, check for NULL and deserialize value into non-nullable column (and return true) or insert default value of nested type (and return false) |
104 | /// If ReturnType is void, deserialize Nullable(T) |
105 | template <typename ReturnType = bool> |
106 | static ReturnType deserializeTextEscaped(IColumn & column, ReadBuffer & istr, const FormatSettings & settings, const DataTypePtr & nested); |
107 | template <typename ReturnType = bool> |
108 | static ReturnType deserializeTextQuoted(IColumn & column, ReadBuffer & istr, const FormatSettings &, const DataTypePtr & nested); |
109 | template <typename ReturnType = bool> |
110 | static ReturnType deserializeTextCSV(IColumn & column, ReadBuffer & istr, const FormatSettings & settings, const DataTypePtr & nested); |
111 | template <typename ReturnType = bool> |
112 | static ReturnType deserializeTextJSON(IColumn & column, ReadBuffer & istr, const FormatSettings &, const DataTypePtr & nested); |
113 | |
114 | private: |
115 | DataTypePtr nested_data_type; |
116 | }; |
117 | |
118 | |
119 | DataTypePtr makeNullable(const DataTypePtr & type); |
120 | DataTypePtr removeNullable(const DataTypePtr & type); |
121 | |
122 | } |
123 | |