mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 13:42:02 +00:00
72 lines
1.5 KiB
C++
72 lines
1.5 KiB
C++
#pragma once
|
||
|
||
#include <DB/Storages/IStorage.h>
|
||
#include <DB/Parsers/TablePropertiesQueriesASTs.h>
|
||
#include <DB/Interpreters/Context.h>
|
||
#include <DB/Interpreters/IInterpreter.h>
|
||
#include <DB/DataStreams/OneBlockInputStream.h>
|
||
#include <DB/DataStreams/BlockIO.h>
|
||
#include <DB/DataStreams/FormatFactory.h>
|
||
#include <DB/DataStreams/copyData.h>
|
||
#include <DB/DataTypes/DataTypesNumberFixed.h>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
|
||
/** Проверить, существует ли таблица. Вернуть одну строку с одним столбцом result типа UInt8 со значением 0 или 1.
|
||
*/
|
||
class InterpreterExistsQuery : public IInterpreter
|
||
{
|
||
public:
|
||
InterpreterExistsQuery(ASTPtr query_ptr_, Context & context_)
|
||
: query_ptr(query_ptr_), context(context_) {}
|
||
|
||
BlockIO execute() override
|
||
{
|
||
BlockIO res;
|
||
res.in = executeImpl();
|
||
res.in_sample = getSampleBlock();
|
||
|
||
return res;
|
||
}
|
||
|
||
private:
|
||
ASTPtr query_ptr;
|
||
Context context;
|
||
|
||
Block getSampleBlock()
|
||
{
|
||
ColumnWithTypeAndName col;
|
||
col.name = "result";
|
||
col.type = new DataTypeUInt8;
|
||
col.column = col.type->createColumn();
|
||
|
||
Block block;
|
||
block.insert(col);
|
||
|
||
return block;
|
||
}
|
||
|
||
BlockInputStreamPtr executeImpl()
|
||
{
|
||
const ASTExistsQuery & ast = typeid_cast<const ASTExistsQuery &>(*query_ptr);
|
||
|
||
bool res = context.isTableExist(ast.database, ast.table);
|
||
|
||
ColumnWithTypeAndName col;
|
||
col.name = "result";
|
||
col.type = new DataTypeUInt8;
|
||
col.column = new ColumnConstUInt8(1, res);
|
||
|
||
Block block;
|
||
block.insert(col);
|
||
|
||
return new OneBlockInputStream(block);
|
||
}
|
||
};
|
||
|
||
|
||
}
|