tkrzw::FileIndex Class Reference

File secondary index implementation with TreeDBM. More...

#include <tkrzw_index.h>

Classes
class	Iterator
	Iterator for each record. More...

Public Member Functions
Status	Open (const std::string &path, bool writable, int32_t options=File::OPEN_DEFAULT, const TreeDBM::TuningParameters &tuning_params=TreeDBM::TuningParameters())
	Opens a database file. More...
Status	Close ()
	Closes the database file. More...
bool	Check (std::string_view key, std::string_view value)
	Checks whether a record exists in the index. More...
std::vector< std::string >	GetValues (std::string_view key, size_t max=0)
	Gets all values of records of a key. More...
Status	Add (std::string_view key, std::string_view value)
	Adds a record. More...
Status	Remove (std::string_view key, std::string_view value)
	Removes a record. More...
Status	Clear ()
	Removes all records. More...
size_t	Count ()
	Gets the number of records. More...
std::unique_ptr< Iterator >	MakeIterator ()
	Makes an iterator for each record. More...

Detailed Description

File secondary index implementation with TreeDBM.

All operations are thread-safe; Multiple threads can access the same database concurrently.

Member Function Documentation

Open()

Status tkrzw::FileIndex::Open	(	const std::string &	path,
		bool	writable,
		int32_t	options = File::OPEN_DEFAULT,
		const TreeDBM::TuningParameters &	tuning_params = TreeDBM::TuningParameters()
	)

Opens a database file.

Parameters

path	A path of the file.
writable	If true, the file is writable. If false, it is read-only.
options	Bit-sum options for opening the file.
tuning_params	A structure for tuning parameters.

Returns

The result status. If the key comparator of the tuning parameter is nullptr, PairLexicalKeyComparator is set implicitly. Other compatible key comparators are PairLexicalCaseKeyComparator, PairDecimalKeyComparator, PairHexadecimalKeyComparator, and PairRealNumberKeyComparator. The alignment power and the maximum page size are also set implicitly to be suitable for random access.

Close()

Status tkrzw::FileIndex::Close

(

)

Closes the database file.

Returns

The result status. Precondition: The database is opened.

Check()

bool tkrzw::FileIndex::Check	(	std::string_view	key,
		std::string_view	value
	)

Checks whether a record exists in the index.

Parameters

key	The key of the record.
value	The value of the record.

GetValues()

std::vector< std::string > tkrzw::FileIndex::GetValues	(	std::string_view	key,
		size_t	max = 0
	)

Gets all values of records of a key.

Parameters

key	The key to look for.
max	The maximum number of values to get. 0 means unlimited.

Returns

All values of the key.

Add()

Status tkrzw::FileIndex::Add	(	std::string_view	key,
		std::string_view	value
	)

Adds a record.

Parameters

key	The key of the record. This can be an arbitrary expression to search the index.
value	The value of the record. This should be a primary value of another database.

Returns

The result status.

Remove()

Status tkrzw::FileIndex::Remove	(	std::string_view	key,
		std::string_view	value
	)

Removes a record.

Parameters

key	The key of the record.
value	The value of the record.

Returns

The result status.

Clear()

Status tkrzw::FileIndex::Clear

(

)

Removes all records.

Returns

The result status.

Count()

size_t tkrzw::FileIndex::Count

(

)

Gets the number of records.

Returns

The number of records.

MakeIterator()

std::unique_ptr< FileIndex::Iterator > tkrzw::FileIndex::MakeIterator

(

)

Makes an iterator for each record.

Returns

The iterator for each record.