1 | #pragma once |
2 | |
3 | #include <string> |
4 | #include <Columns/IColumn.h> |
5 | #include <Formats/FormatSettings.h> |
6 | #include <Parsers/IdentifierQuotingStyle.h> |
7 | |
8 | |
9 | namespace DB |
10 | { |
11 | struct DictionaryStructure; |
12 | class WriteBuffer; |
13 | |
14 | |
15 | /** Builds a query to load data from external database. |
16 | */ |
17 | struct ExternalQueryBuilder |
18 | { |
19 | const DictionaryStructure & dict_struct; |
20 | std::string db; |
21 | std::string table; |
22 | std::string schema; |
23 | const std::string & where; |
24 | |
25 | IdentifierQuotingStyle quoting_style; |
26 | |
27 | |
28 | ExternalQueryBuilder( |
29 | const DictionaryStructure & dict_struct_, |
30 | const std::string & db_, |
31 | const std::string & table_, |
32 | const std::string & where_, |
33 | IdentifierQuotingStyle quoting_style_); |
34 | |
35 | /** Generate a query to load all data. */ |
36 | std::string composeLoadAllQuery() const; |
37 | |
38 | /** Generate a query to load data after certain time point */ |
39 | std::string composeUpdateQuery(const std::string & update_field, const std::string & time_point) const; |
40 | |
41 | /** Generate a query to load data by set of UInt64 keys. */ |
42 | std::string composeLoadIdsQuery(const std::vector<UInt64> & ids); |
43 | |
44 | /** Generate a query to load data by set of composite keys. |
45 | * There are two methods of specification of composite keys in WHERE: |
46 | * 1. (x = c11 AND y = c12) OR (x = c21 AND y = c22) ... |
47 | * 2. (x, y) IN ((c11, c12), (c21, c22), ...) |
48 | */ |
49 | enum LoadKeysMethod |
50 | { |
51 | AND_OR_CHAIN, |
52 | IN_WITH_TUPLES, |
53 | }; |
54 | |
55 | std::string composeLoadKeysQuery(const Columns & key_columns, const std::vector<size_t> & requested_rows, LoadKeysMethod method); |
56 | |
57 | |
58 | private: |
59 | const FormatSettings format_settings; |
60 | |
61 | /// Expression in form (x = c1 AND y = c2 ...) |
62 | void composeKeyCondition(const Columns & key_columns, const size_t row, WriteBuffer & out) const; |
63 | |
64 | /// Expression in form (x, y, ...) |
65 | std::string composeKeyTupleDefinition() const; |
66 | |
67 | /// Expression in form (c1, c2, ...) |
68 | void composeKeyTuple(const Columns & key_columns, const size_t row, WriteBuffer & out) const; |
69 | |
70 | /// Write string with specified quoting style. |
71 | void writeQuoted(const std::string & s, WriteBuffer & out) const; |
72 | }; |
73 | |
74 | } |
75 | |