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44 lines
1.1 KiB
C++
44 lines
1.1 KiB
C++
#pragma once
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#include <Interpreters/Context.h>
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#include <Parsers/IAST.h>
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#include <Parsers/ASTIdentifier.h>
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#include <Common/typeid_cast.h>
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#include <Interpreters/InDepthNodeVisitor.h>
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#include <Interpreters/IdentifierSemantic.h>
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namespace DB
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{
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/// If node is ASTIdentifier try to extract external_storage.
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class ExternalTablesMatcher
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{
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public:
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struct Data
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{
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const Context & context;
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Tables & external_tables;
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};
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static void visit(ASTPtr & ast, Data & data)
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{
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if (auto * t = typeid_cast<ASTIdentifier *>(ast.get()))
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visit(*t, ast, data);
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}
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static bool needChildVisit(ASTPtr &, const ASTPtr &) { return true; }
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private:
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static void visit(const ASTIdentifier & node, ASTPtr &, Data & data)
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{
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if (auto opt_name = IdentifierSemantic::getTableName(node))
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if (StoragePtr external_storage = data.context.tryGetExternalTable(*opt_name))
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data.external_tables[*opt_name] = external_storage;
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}
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};
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/// Finds in the query the usage of external tables. Fills in external_tables.
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using ExternalTablesVisitor = InDepthNodeVisitor<ExternalTablesMatcher, false>;
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}
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