blob: d8a26f1def48d6c25e62ac1a789b8c0067e44c7b (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
#pragma once
#include <Storages/IStorage.h>
namespace DB
{
class Context;
/** Implements storage for the system table One.
* The table contains a single column of dummy UInt8 and a single row with a value of 0.
* Used when the table is not specified in the query.
* Analog of the DUAL table in Oracle and MySQL.
*/
class StorageSystemOne final : public IStorage
{
public:
explicit StorageSystemOne(const StorageID & table_id_);
std::string getName() const override { return "SystemOne"; }
Pipe read(
const Names & column_names,
const StorageSnapshotPtr & storage_snapshot,
SelectQueryInfo & query_info,
ContextPtr context,
QueryProcessingStage::Enum processed_stage,
size_t max_block_size,
size_t num_streams) override;
bool isSystemStorage() const override { return true; }
bool supportsTransactions() const override { return true; }
};
}
|
