On-memory Hash Database — MDB

New in version 0.1.2.

MDB

class tokyo.cabinet.MDB([bnum])

Parameter:bnum – the number of elements in a bucket array. If omitted or specified as 0, the default value (65536) is used.

Example:

from tokyo.cabinet 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 str (Python2) or bytes (Python3).

See also

API of On-memory Hash Database

len(mdb)

Return the number of records in the database mdb.

mdb[key]

Return the value of mdb‘s record corresponding to key. Raises KeyError if key is not in the database.

mdb[key] = value

Set mdb[key] to value.

del mdb[key]

Remove mdb[key] from mdb. Raises KeyError if key is not in the database.

key in mdb

Return True if mdb has a key key, else False.

key not in mdb

Equivalent to not key in mdb.

iter(mdb)

Return an iterator over the keys of the database.

clear()

Remove all records from the database.

get(key)

Return the value corresponding to key. Equivalent to mdb[key].

New in version 0.2.0.

remove(key)

Delete a record from the database. Equivalent to del mdb[key].

New in version 0.2.0.

put(key, value)

Store a record in the database. Equivalent to mdb[key] = value.

putkeep(key, value)

Store a record in the database, unlike the standard forms (mdb[key] = value or put()), this method raises KeyError if key is already in the database.

putcat(key, value)

Concatenate a value at the end of an existing one. If there is no corresponding record, a new record is stored.

iterkeys()

Return an iterator over the database’s keys.

New in version 0.6.1.

itervalues()

Return an iterator over the database’s values.

New in version 0.6.1.

iteritems()

Return an iterator over the database’s items ((key, value) pairs).

New in version 0.6.1.

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.

size

The size in bytes of the database.