lmdb::dbi Class Reference

Resource class for MDB_dbi handles. More...

#include <lmdb++.h>

Public Member Functions
	dbi () noexcept
	Constructor. More...
	dbi (const MDB_dbi handle) noexcept
	Constructor. More...
	~dbi () noexcept
	Destructor. More...
	operator MDB_dbi () const noexcept
	Returns the underlying MDB_dbi handle. More...
MDB_dbi	handle () const noexcept
	Returns the underlying MDB_dbi handle. More...
MDB_stat	stat (MDB_txn *const txn) const
	Returns statistics for this database. More...
unsigned int	flags (MDB_txn *const txn) const
	Retrieves the flags for this database handle. More...
std::size_t	size (MDB_txn *const txn) const
	Returns the number of records in this database. More...
void	drop (MDB_txn *const txn, const bool del=false)
dbi &	set_compare (MDB_txn *const txn, MDB_cmp_func *const cmp=nullptr)
	Sets a custom key comparison function for this database. More...
bool	get (MDB_txn *const txn, const std::string_view key, std::string_view &data)
	Retrieves a key/value pair from this database. More...
bool	put (MDB_txn *const txn, const std::string_view key, std::string_view data, const unsigned int flags=default_put_flags)
	Stores a key/value pair into this database. More...
bool	del (MDB_txn *const txn, const std::string_view key)
	Removes a key from this database. More...
bool	del (MDB_txn *const txn, const std::string_view key, const std::string_view val)
	Removes a key/value pair from this database. More...

Static Public Member Functions
static dbi	open (MDB_txn *const txn, const char *const name=nullptr, const unsigned int flags=default_flags)
	Opens a database handle. More...

Static Public Attributes
static constexpr unsigned int	default_flags = 0
static constexpr unsigned int	default_put_flags = 0

Protected Attributes
MDB_dbi	_handle {(std::numeric_limits<MDB_dbi>::max)()}

Detailed Description

Resource class for MDB_dbi handles.

See also

http://symas.com/mdb/doc/group__mdb.html#gadbe68a06c448dfb62da16443d251a78b

Constructor & Destructor Documentation

dbi() [1/2]

lmdb::dbi::dbi ( )

inlinenoexcept

Constructor.

Note

Creates an uninitialized dbi instance. You must move or move-assign a valid dbi instance onto it before you can use it.

dbi() [2/2]

lmdb::dbi::dbi ( const MDB_dbi  handle )

inlinenoexcept

Constructor.

Parameters

handle

a valid MDB_dbi handle

~dbi()

lmdb::dbi::~dbi ( )

inlinenoexcept

Destructor.

Member Function Documentation

del() [1/2]

bool lmdb::dbi::del ( MDB_txn *const  txn, const std::string_view  key  )

inline

Removes a key from this database.

Parameters

txn	a transaction handle
key

Exceptions

lmdb::error

on failure

del() [2/2]

bool lmdb::dbi::del ( MDB_txn *const  txn, const std::string_view  key, const std::string_view  val  )

inline

Removes a key/value pair from this database.

Parameters

txn	a transaction handle
key
val

Exceptions

lmdb::error

on failure

drop()

void lmdb::dbi::drop ( MDB_txn *const  txn, const bool  del = false  )

inline

Parameters

txn	a transaction handle
del

Exceptions

lmdb::error

on failure

flags()

unsigned int lmdb::dbi::flags ( MDB_txn *const  txn ) const

inline

Retrieves the flags for this database handle.

Parameters

txn	a transaction handle

Exceptions

lmdb::error

on failure

get()

bool lmdb::dbi::get ( MDB_txn *const  txn, const std::string_view  key, std::string_view &  data  )

inline

Retrieves a key/value pair from this database.

Parameters

txn	a transaction handle
key
data

Exceptions

lmdb::error

on failure

handle()

MDB_dbi lmdb::dbi::handle ( ) const

inlinenoexcept

Returns the underlying MDB_dbi handle.

open()

static dbi lmdb::dbi::open ( MDB_txn *const  txn, const char *const  name = nullptr, const unsigned int  flags = default_flags  )

inlinestatic

Opens a database handle.

Parameters

txn	the transaction handle
name
flags

Exceptions

lmdb::error

on failure

operator MDB_dbi()

lmdb::dbi::operator MDB_dbi ( ) const

inlinenoexcept

Returns the underlying MDB_dbi handle.

put()

bool lmdb::dbi::put ( MDB_txn *const  txn, const std::string_view  key, std::string_view  data, const unsigned int  flags = default_put_flags  )

inline

Stores a key/value pair into this database.

Parameters

txn	a transaction handle
key
data
flags

Exceptions

lmdb::error

on failure

set_compare()

dbi& lmdb::dbi::set_compare ( MDB_txn *const  txn, MDB_cmp_func *const  cmp = nullptr  )

inline

Sets a custom key comparison function for this database.

Parameters

txn	a transaction handle
cmp	the comparison function

Exceptions

lmdb::error

on failure

size()

std::size_t lmdb::dbi::size ( MDB_txn *const  txn ) const

inline

Returns the number of records in this database.

Parameters

txn	a transaction handle

Exceptions

lmdb::error

on failure

stat()

MDB_stat lmdb::dbi::stat ( MDB_txn *const  txn ) const

inline

Returns statistics for this database.

Parameters

txn	a transaction handle

Exceptions

lmdb::error

on failure

Member Data Documentation

_handle

MDB_dbi lmdb::dbi::_handle {(std::numeric_limits<MDB_dbi>::max)()}

protected

default_flags

constexpr unsigned int lmdb::dbi::default_flags = 0

staticconstexpr

default_put_flags

constexpr unsigned int lmdb::dbi::default_put_flags = 0

staticconstexpr

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The documentation for this class was generated from the following file:

• lmdb++.h