The DBM class provides a wrapper to a Unix-style dbm or Database Manager library.
Dbm databases do not have tables or columns; they are simple key-value data stores, like a Ruby Hash except not resident in RAM. Keys and values must be strings.
The exact library used depends on how Ruby was compiled. It could be any of the following:
- The original ndbm library is released in 4.3BSD. It is based on dbm library in Unix Version 7 but has different API to support multiple databases in a process.
- Berkeley DB versions 1 thru 5, also known as BDB and Sleepycat DB, now owned by Oracle Corporation.
- Berkeley DB 1.x, still found in 4.4BSD derivatives (FreeBSD, OpenBSD, etc).
- gdbm, the GNU implementation of dbm.
- qdbm, another open source reimplementation of dbm.
All of these dbm implementations have their own Ruby interfaces available, which provide richer (but varying) APIs.
Add this line to your application's Gemfile:
gem 'dbm'And then execute:
$ bundle
Or install it yourself as:
$ gem install dbm
require 'dbm'
db = DBM.open('rfcs', 0666, DBM::WRCREAT)
db['822'] = 'Standard for the Format of ARPA Internet Text Messages'
db['1123'] = 'Requirements for Internet Hosts - Application and Support'
db['3068'] = 'An Anycast Prefix for 6to4 Relay Routers'
puts db['822']After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/dbm.
The gem is available as open source under the terms of the 2-Clause BSD License.