ClickHouse/dbms/include/DB/Parsers/ParserCreateQuery.h

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#pragma once
#include <DB/Parsers/IParserBase.h>
#include <DB/Parsers/ExpressionElementParsers.h>
#include <DB/Parsers/ExpressionListParsers.h>
#include <DB/Parsers/ASTNameTypePair.h>
#include <DB/Parsers/ASTColumnDeclaration.h>
#include <DB/Parsers/ASTIdentifier.h>
#include <DB/Parsers/CommonParsers.h>
#include <Poco/String.h>
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namespace DB
{
/** Вложенная таблица. Например, Nested(UInt32 CounterID, FixedString(2) UserAgentMajor)
*/
class ParserNestedTable : public IParserBase
{
protected:
const char * getName() const { return "nested table"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
};
/** Параметрический тип или Storage. Например:
* FixedString(10) или
* Partitioned(Log, ChunkID) или
* Nested(UInt32 CounterID, FixedString(2) UserAgentMajor)
* Результат парсинга - ASTFunction с параметрами или без.
*/
class ParserIdentifierWithParameters : public IParserBase
{
protected:
const char * getName() const { return "identifier with parameters"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
};
/** Тип или Storage, возможно, параметрический. Например, UInt8 или примеры из ParserIdentifierWithParameters
* Результат парсинга - ASTFunction с параметрами или без.
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*/
class ParserIdentifierWithOptionalParameters : public IParserBase
{
protected:
const char * getName() const { return "identifier with optional parameters"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
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};
template <class NameParser>
class IParserNameTypePair : public IParserBase
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{
protected:
const char * getName() const { return "name and type pair"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
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};
/** Имя и тип через пробел. Например, URL String. */
typedef IParserNameTypePair<ParserIdentifier> ParserNameTypePair;
/** Имя и тип через пробел. Имя может содержать точку. Например, Hits.URL String. */
typedef IParserNameTypePair<ParserCompoundIdentifier> ParserCompoundNameTypePair;
template <class NameParser>
bool IParserNameTypePair<NameParser>::parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected)
{
NameParser name_parser;
ParserIdentifierWithOptionalParameters type_parser;
ParserWhiteSpaceOrComments ws_parser;
Pos begin = pos;
ASTPtr name, type;
if (name_parser.parse(pos, end, name, expected)
&& ws_parser.ignore(pos, end, expected)
&& type_parser.parse(pos, end, type, expected))
{
ASTNameTypePair * name_type_pair = new ASTNameTypePair(StringRange(begin, pos));
node = name_type_pair;
name_type_pair->name = typeid_cast<ASTIdentifier &>(*name).name;
name_type_pair->type = type;
name_type_pair->children.push_back(type);
return true;
}
pos = begin;
return false;
}
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/** Список столбцов. */
class ParserNameTypePairList : public IParserBase
{
protected:
const char * getName() const { return "name and type pair list"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
};
template <class NameParser>
class IParserColumnDeclaration : public IParserBase
{
protected:
const char * getName() const { return "column declaration"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
};
typedef IParserColumnDeclaration<ParserIdentifier> ParserColumnDeclaration;
typedef IParserColumnDeclaration<ParserCompoundIdentifier> ParserCompoundColumnDeclaration;
template <class NameParser>
bool IParserColumnDeclaration<NameParser>::parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected)
{
NameParser name_parser;
ParserIdentifierWithOptionalParameters type_parser;
ParserWhiteSpaceOrComments ws;
ParserString s_default{"DEFAULT", true, true};
ParserString s_materialized{"MATERIALIZED", true, true};
ParserString s_alias{"ALIAS", true, true};
ParserTernaryOperatorExpression expr_parser;
const auto begin = pos;
const auto reset_pos_and_return = [&pos, begin] {
pos = begin;
return false;
};
/// mandatory column name
ASTPtr name;
if (!name_parser.parse(pos, end, name, expected))
return false;
ws.ignore(pos, end, expected);
/** column name should be followed by type name if it
* is not immediately followed by {DEFAULT, MATERIALIZED, ALIAS} */
ASTPtr type;
const auto fallback_pos = pos;
if (!s_default.check(pos, end, expected) &&
!s_materialized.check(pos, end, expected) &&
!s_alias.check(pos, end, expected))
{
if (type_parser.parse(pos, end, type, expected))
ws.ignore(pos, end, expected);
}
else
pos = fallback_pos;
/// parse {DEFAULT, MATERIALIZED, ALIAS}
String default_specifier;
ASTPtr default_expression;
const auto pos_before_specifier = pos;
if (s_default.ignore(pos, end, expected) ||
s_materialized.ignore(pos, end, expected) ||
s_alias.ignore(pos, end, expected))
{
default_specifier = Poco::toUpper(std::string{pos_before_specifier, pos});
/// should be followed by an expression
ws.ignore(pos, end, expected);
if (!expr_parser.parse(pos, end, default_expression, expected))
return reset_pos_and_return();
}
else if (!type)
return reset_pos_and_return(); /// reject sole column name without type
const auto column_declaration = new ASTColumnDeclaration{StringRange{begin, pos}};
node = column_declaration;
column_declaration->name = typeid_cast<ASTIdentifier &>(*name).name;
if (type)
{
column_declaration->type = type;
column_declaration->children.push_back(std::move(type));
}
if (default_expression)
{
column_declaration->default_specifier = default_specifier;
column_declaration->default_expression = default_expression;
column_declaration->children.push_back(std::move(default_expression));
}
return true;
}
class ParserColumnDeclarationList : public IParserBase
{
protected:
const char * getName() const { return "column declaration list"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
};
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/** ENGINE = name. */
class ParserEngine : public IParserBase
{
protected:
const char * getName() const { return "ENGINE"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
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};
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/** Запрос типа такого:
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* CREATE|ATTACH TABLE [IF NOT EXISTS] [db.]name
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* (
* name1 type1,
* name2 type2,
* ...
* ) ENGINE = engine
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*
* Или:
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* CREATE|ATTACH TABLE [IF NOT EXISTS] [db.]name AS [db2.]name2 [ENGINE = engine]
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*
* Или:
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* CREATE|ATTACH TABLE [IF NOT EXISTS] [db.]name AS ENGINE = engine SELECT ...
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*
* Или:
* CREATE|ATTACH DATABASE db
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*
* Или:
* CREATE|ATTACH [MATERIALIZED] VIEW [IF NOT EXISTS] [db.]name [ENGINE = engine] [POPULATE] AS SELECT ...
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*/
class ParserCreateQuery : public IParserBase
{
protected:
const char * getName() const { return "CREATE TABLE or ATTACH TABLE query"; }
bool parseImpl(Pos & pos, Pos end, ASTPtr & node, Expected & expected);
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};
}