goldfishdb
Goldfish DB is a really simple database for in-memory Ruby objects. If you're working with lots of ephemeral data that doesn't need to be persisted, but that you need to be able to query in multiple ways, you might find it useful.
It provides a simple way of defining multiple indexes over a set of data, taking care of the manual book-kepping that would otherwise be necessary to maintain the indexes.
There are a few important things to be aware of:
- No persistance - all data lives in memory and will disappear with your Ruby process.
- Only supports querying for equality, i.e. range lookups aren't possible.
- Currently not threadsafe.
Example
require "goldfish"
animals = Goldfish.table do |animal|
# The block passed to the table method defines the primary key for
# each object that will be added to the table.
animal.id
end
animals.index(:name) { |animal| animal.name }
animals.index(:dangerous) do |animal|
["lion", "pirana", "tarantula"].includes? animal.type.downcase
end
# Queries return a DataSet object, which you can chain additional
# conditions on to:
dataset = animals.filter(dangerous: true)
dataset.map { |animal| animal.name } # => ["Lion", "Pirana"]
dataset.filter(name: "Lion").to_a # => ["Lion"]