Summary

Ruby extension for GNU dbm (gdbm) – a simple database engine for storing key-value pairs on disk.

Description

GNU dbm is a library for simple databases. A database is a file that stores key-value pairs. Gdbm allows the user to store, retrieve, and delete data by key. It furthermore allows a non-sorted traversal of all key-value pairs. A gdbm database thus provides the same functionality as a hash. As with objects of the Hash class, elements can be accessed with []. Furthermore, GDBM mixes in the Enumerable module, thus providing convenient methods such as #find, #collect, #map, etc.

A process is allowed to open several different databases at the same time. A process can open a database as a “reader” or a “writer”. Whereas a reader has only read-access to the database, a writer has read- and write-access. A database can be accessed either by any number of readers or by exactly one writer at the same time.

Examples

  1. Opening/creating a database, and filling it with some entries:

    require 'gdbm'

gdbm = GDBM.new("fruitstore.db")
gdbm["ananas"]    = "3"
gdbm["banana"]    = "8"
gdbm["cranberry"] = "4909"
gdbm.close

  2. Reading out a database:

    require 'gdbm'

gdbm = GDBM.new("fruitstore.db")
gdbm.each_pair do |key, value|
  print "#{key}: #{value}\n"
end
gdbm.close

produces

  banana: 8
  ananas: 3
  cranberry: 4909

Links

Constants

READER = flag for #new and #open

WRITER = flag for #new and #open

WRCREAT = flag for #new and #open

NEWDB = flag for #new and #open

FAST = INT2FIX(GDBM_FAST)

SYNC = INT2FIX(GDBM_SYNC)

NOLOCK = INT2FIX(GDBM_NOLOCK)

VERSION = rb_str_new2(gdbm_version)

Attributes

Show files where this class is defined (1 file)
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