.. _MDB: .. currentmodule:: tokyocabinet ======================================== On-memory Hash Database --- :class:`MDB` ======================================== .. versionadded:: 0.1.2 :class:`MDB` ============ .. class:: MDB([bnum]) :param bnum: the number of elements in a bucket array. If omitted or specified as 0, the default value (65536) is used. Example:: from tokyocabinet import * mdb = MDB() # store records for key, value in [("foo", "hop"), ("bar", "step"), ("baz", "jump")]: mdb[key] = value # retrieve one record print(mdb["foo"]) # traverse records for key in mdb: print(key, mdb[key]) .. note:: For all methods taking either a *key* argument or a pair *(key, value)*, *key* and *value* must be either :class:`str` (Python2) or :class:`bytes` (Python3). .. seealso:: `API of On-memory Hash Database `_ .. describe:: len(mdb) Return the number of records in the database *mdb*. .. describe:: mdb[key] Return the value of *mdb*'s record corresponding to *key*. Raises :exc:`KeyError` if *key* is not in the database. .. describe:: mdb[key] = value Set ``mdb[key]`` to *value*. .. describe:: del mdb[key] Remove ``mdb[key]`` from *mdb*. Raises :exc:`KeyError` if *key* is not in the database. .. describe:: key in mdb Return ``True`` if *mdb* has a key *key*, else ``False``. .. describe:: key not in mdb Equivalent to ``not key in mdb``. .. describe:: iter(mdb) Return an iterator over the keys of the database. .. method:: clear Remove all records from the database. .. method:: get(key) Return the value corresponding to *key*. Equivalent to ``mdb[key]``. .. versionadded:: 0.2.0 .. method:: remove(key) Delete a record from the database. Equivalent to ``del mdb[key]``. .. versionadded:: 0.2.0 .. method:: put(key, value) Store a record in the database. Equivalent to ``mdb[key] = value``. .. method:: putkeep(key, value) Store a record in the database, unlike the standard forms (``mdb[key] = value`` or :meth:`put`), this method raises :exc:`KeyError` if *key* is already in the database. .. method:: putcat(key, value) Concatenate a value at the end of an existing one. If there is no corresponding record, a new record is stored. .. method:: searchkeys(prefix[, max]) Return a frozenset of keys starting with *prefix*. If given, *max* is the maximum number of keys to fetch, if omitted or specified as a negative value no limit is applied. Methods :meth:`keys`, :meth:`values` and :meth:`items` are not yet implemented (mainly because I didn't settle on how to do it: should they return :class:`Iterable`, :class:`Iterator`, :class:`MappingView`, etc.?). Any help would be greatly appreciated in this matter. For the time being, for those of you who really need these methods, it's trivial to implement them in python. Here is an example using generators:: from tokyocabinet import MDB as _MDB class MDB(_MDB): def keys(self): return (key for key in self) def values(self): return (self[key] for key in self) def items(self): return ((key, self[key]) for key in self) .. attribute:: size The size in bytes of the database.