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#pragma once
#include <optional>
#include <vector>
#include <memory>
#include <unordered_map>
#include <Parsers/ASTAlterQuery.h>
#include <Storages/IStorage_fwd.h>
#include <DataTypes/IDataType.h>
#include <Core/Names.h>
namespace DB
{
class Context;
class WriteBuffer;
class ReadBuffer;
/// Represents set of actions which should be applied
/// to values from set of columns which satisfy predicate.
struct MutationCommand
{
ASTPtr ast = {}; /// The AST of the whole command
enum Type
{
EMPTY, /// Not used.
DELETE,
UPDATE,
MATERIALIZE_INDEX,
MATERIALIZE_PROJECTION,
READ_COLUMN, /// Read column and apply conversions (MODIFY COLUMN alter query).
DROP_COLUMN,
DROP_INDEX,
DROP_PROJECTION,
MATERIALIZE_TTL,
RENAME_COLUMN,
MATERIALIZE_COLUMN,
ALTER_WITHOUT_MUTATION, /// pure metadata command, currently unusned
};
Type type = EMPTY;
/// WHERE part of mutation
ASTPtr predicate = {};
/// Columns with corresponding actions
std::unordered_map<String, ASTPtr> column_to_update_expression = {};
/// For MATERIALIZE INDEX and PROJECTION
String index_name = {};
String projection_name = {};
/// For MATERIALIZE INDEX, UPDATE and DELETE.
ASTPtr partition = {};
/// For reads, drops and etc.
String column_name = {};
DataTypePtr data_type = {}; /// Maybe empty if we just want to drop column
/// We need just clear column, not drop from metadata.
bool clear = false;
/// Column rename_to
String rename_to = {};
/// If parse_alter_commands, than consider more Alter commands as mutation commands
static std::optional<MutationCommand> parse(ASTAlterCommand * command, bool parse_alter_commands = false);
/// This command shouldn't stick with other commands
bool isBarrierCommand() const;
};
/// Multiple mutation commands, possible from different ALTER queries
class MutationCommands : public std::vector<MutationCommand>
{
public:
std::shared_ptr<ASTExpressionList> ast(bool with_pure_metadata_commands = false) const;
void writeText(WriteBuffer & out, bool with_pure_metadata_commands) const;
void readText(ReadBuffer & in);
std::string toString() const;
bool hasNonEmptyMutationCommands() const;
/// These set of commands contain barrier command and shouldn't
/// stick with other commands. Commands from one set have already been validated
/// to be executed without issues on the creation state.
bool containBarrierCommand() const;
};
using MutationCommandsConstPtr = std::shared_ptr<MutationCommands>;
}
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