"""Generic interface to all dbm clones.
d = dbm.open(file, 'w', 0666)
d = anydbm.open(file, 'w')
The returned object is a dbhash, gdbm, dbm or dumbdbm object,
dependent on the type of database being opened (determined by whichdb
module) in the case of an existing dbm. If the dbm does not exist and
the create or new flag ('c' or 'n') was specified, the dbm type will
be determined by the availability of the modules (tested in the above
It has the following interface (key and data are strings):
d[key] = data # store data at key (may override data at
data = d[key] # retrieve data at key (raise KeyError if no
del d[key] # delete data stored at key (raises KeyError
flag = key in d # true if the key exists
list = d.keys() # return a list of all existing keys (slow!)
Future versions may change the order in which implementations are
tested for existence, add interfaces to other dbm-like
The open function has an optional second argument. This can be 'r',
for read-only access, 'w', for read-write access of an existing
database, 'c' for read-write access to a new or existing database, and
'n' for read-write access to a new database. The default is 'r'.
Note: 'r' and 'w' fail if the database doesn't exist; 'c' creates it
only if it doesn't exist; and 'n' always creates a new database.
_names
= ['dbhash', 'gdbm', 'dbm', 'dumbdbm']
_errors
.append(_mod
.error
)
raise ImportError, "no dbm clone found; tried %s" % _names
def open(file, flag
= 'r', mode
= 0666):
# guess the type of an existing database
from whichdb
import whichdb
if 'c' in flag
or 'n' in flag
:
# file doesn't exist and the new
# flag was used so use default type
raise error
, "need 'c' or 'n' flag to open new db"
# db type cannot be determined
raise error
, "db type could not be determined"
return mod
.open(file, flag
, mode
)