7.6 Standard Modules anydbm and dumbdbm

   

anydbm is a generic interface to variants of the DBM database-DBM, GDBM, or dbhash. If none of these modules is installed, the slow-but-simple implementation in module dumbdbm will be used. Both modules provide the same interface:

open (filename[, flag, mode])

Open the database file filename and return a corresponding object. The optional flag argument can be 'r' to open an existing database for reading only, 'w' to open an existing database for reading and writing, 'c' to create the database if it doesn't exist, or 'n', which will always create a new empty database. If not specified, the default value is 'r'.

The optional mode argument is the Unix mode of the file, used only when the database has to be created. It defaults to octal 0666 (and will be modified by the prevailing umask).

The object returned by open() supports most of the same functionality as dictionaries; keys and their corresponding values can be stored, retrieved, and deleted, and the has_key() and keys() methods are available. Keys and values must always be strings.

Both modules also export the exception error, which is raised for various problems. The anydbm.error exception is simply a different name for the error exception of the underlying implementation module used.