mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-11 18:14:03 +00:00
105 lines
2.7 KiB
C++
105 lines
2.7 KiB
C++
#pragma once
|
||
|
||
#include <DB/Storages/IStorage.h>
|
||
#include <DB/Parsers/TablePropertiesQueriesASTs.h>
|
||
#include <DB/Parsers/ASTIdentifier.h>
|
||
#include <DB/Interpreters/Context.h>
|
||
#include <DB/DataStreams/OneBlockInputStream.h>
|
||
#include <DB/DataStreams/BlockIO.h>
|
||
#include <DB/DataStreams/copyData.h>
|
||
#include <DB/DataTypes/DataTypesNumberFixed.h>
|
||
#include <DB/DataTypes/DataTypeString.h>
|
||
#include <DB/Columns/ColumnString.h>
|
||
|
||
|
||
namespace DB
|
||
{
|
||
|
||
|
||
/** Проверить, существует ли таблица. Вернуть одну строку с одним столбцом result типа UInt8 со значением 0 или 1.
|
||
*/
|
||
class InterpreterDescribeQuery
|
||
{
|
||
public:
|
||
InterpreterDescribeQuery(ASTPtr query_ptr_, Context & context_)
|
||
: query_ptr(query_ptr_), context(context_) {}
|
||
|
||
BlockIO execute()
|
||
{
|
||
BlockIO res;
|
||
res.in = executeImpl();
|
||
res.in_sample = getSampleBlock();
|
||
|
||
return res;
|
||
}
|
||
|
||
BlockInputStreamPtr executeAndFormat(WriteBuffer & buf)
|
||
{
|
||
Block sample = getSampleBlock();
|
||
ASTPtr format_ast = dynamic_cast<ASTExistsQuery &>(*query_ptr).format;
|
||
String format_name = format_ast ? dynamic_cast<ASTIdentifier &>(*format_ast).name : "TabSeparated";
|
||
|
||
BlockInputStreamPtr in = executeImpl();
|
||
BlockOutputStreamPtr out = context.getFormatFactory().getOutput(format_name, buf, sample);
|
||
|
||
copyData(*in, *out);
|
||
|
||
return in;
|
||
}
|
||
|
||
private:
|
||
ASTPtr query_ptr;
|
||
Context context;
|
||
|
||
Block getSampleBlock()
|
||
{
|
||
Block block;
|
||
|
||
ColumnWithNameAndType col;
|
||
col.name = "name";
|
||
col.type = new DataTypeString;
|
||
|
||
block.insert(col);
|
||
|
||
col.name = "type";
|
||
|
||
block.insert(col);
|
||
|
||
return block;
|
||
}
|
||
|
||
BlockInputStreamPtr executeImpl()
|
||
{
|
||
const ASTShowCreateQuery & ast = dynamic_cast<const ASTShowCreateQuery &>(*query_ptr);
|
||
|
||
NamesAndTypesList columns;
|
||
|
||
{
|
||
Poco::ScopedLock<Poco::Mutex> lock(context.getMutex());
|
||
|
||
if (!context.isTableExist(ast.database, ast.table))
|
||
throw Exception("Table " + (ast.database.empty() ? "" : ast.database + ".") + ast.table + " doesn't exist", ErrorCodes::UNKNOWN_TABLE);
|
||
|
||
columns = context.getTable(ast.database, ast.table)->getColumnsList();
|
||
}
|
||
|
||
ColumnString * name_column = new ColumnString;
|
||
ColumnString * type_column = new ColumnString;
|
||
|
||
Block block;
|
||
block.insert(ColumnWithNameAndType(name_column, new DataTypeString, "name"));
|
||
block.insert(ColumnWithNameAndType(type_column, new DataTypeString, "type"));
|
||
|
||
for (NamesAndTypesList::iterator it = columns.begin(); it != columns.end(); ++it)
|
||
{
|
||
name_column->insert(it->first);
|
||
type_column->insert(it->second->getName());
|
||
}
|
||
|
||
return new OneBlockInputStream(block);
|
||
}
|
||
};
|
||
|
||
|
||
}
|