ClickHouse/dbms/src/Storages/StorageInMemoryMetadata.h
2019-12-27 22:04:30 +03:00

39 lines
1.4 KiB
C++

#pragma once
#include <Storages/ColumnsDescription.h>
#include <Storages/IndicesDescription.h>
#include <Storages/ConstraintsDescription.h>
#include <Parsers/IAST_fwd.h>
namespace DB
{
/// Structure represent table metadata stored in memory.
/// Only one storage engine support all fields -- MergeTree.
/// Complete table AST can be recreated from this struct.
struct StorageInMemoryMetadata
{
/// Columns of table with their names, types,
/// defaults, comments, etc. All table engines have columns.
ColumnsDescription columns;
/// Table indices. Currently supported for MergeTree only.
IndicesDescription indices;
/// Table constraints. Currently supported for MergeTree only.
ConstraintsDescription constraints;
/// PARTITION BY expression. Currently supported for MergeTree only.
ASTPtr partition_by_ast = nullptr;
/// ORDER BY expression. Required field for all MergeTree tables
/// even in old syntax MergeTree(partition_key, order_by, ...)
ASTPtr order_by_ast = nullptr;
/// PRIMARY KEY expression. If absent, than equal to order_by_ast.
ASTPtr primary_key_ast = nullptr;
/// TTL expression for whole table. Supported for MergeTree only.
ASTPtr ttl_for_table_ast = nullptr;
/// SAMPLE BY expression. Supported for MergeTree only.
ASTPtr sample_by_ast = nullptr;
/// SETTINGS expression. Supported for MergeTree, Buffer and Kafka.
ASTPtr settings_ast = nullptr;
};
}