An embeddable file based Mongo compatible database. Think SQLite for NoSQL.
NoSQL is a complicated and touchy subject these days. Some people love it, some people hate it. Some proponents say it gives them flexibility in how they structure their data so they can focus on application logic rather than how data is stored. Opponents say that "NoSQL is for people who don't understand relational databases" (that's a quote, source provided upon request).
Every flavor of database software has its strengths and weaknesses. The strengths are the result of optimization, the weaknesses the result of informed decisions (at least, I hope that's how it works). MongoLiteDB is no different. The things we want to optimize are ease of use and well... ease of use.
The project came about via a random weekend hack. I wanted to play around with sinatra and datamapper and realized that I either had to a) use SQLite and deal with schema migrations or b) run a MongoDB server. Since my data format was going to be constantly in flux, I didn't want to deal with schema migrations. And having to run an external service (as well as install mongodb on my laptop) was a pain. I expected less than 100 db entries would be needed for my application. I thought to my self, "Is there a database that neither requires a schema nor an external service?" I couldn't find one. So I built this instead. It has the ease of setup that SQLite provides along with the ease of use that MongoDB provides. Like SQLite, it uses only a single file to store all data. Like MongoDB, no schema is required. Anything that is JSONable can be stored.
Performance sucks. As of version 0.0.2:
I'm literally dumping one big json object to a file. To perform queries, I read it in and iterate over every document that is nested inside it. Performance is therefore O(n) where n is the number of documents in the database. But I don't really care. For my use case, performance is overrated. It should be more than adequate for databases with less than 1000 entries.
It was designed to be query compatible with MongoDB. I haven't implemented everything, but quite a bit is done. An example of usage is as follows:
require 'mongolitedb'
require 'pp'
filename = "demo.mglite"
db = MongoLiteDB.new filename
db.insert({
"first_name" => "Joan",
"last_name" => "Of Arc",
"age" => 15,
"armor_size" => "small"
})
db.insert({
"first_name" => "Joan",
"last_name" => "From Madmen",
"age" => 30,
"lipstick_color" => "red"
})
db.insert({
"first_name" => "Joan",
"last_name" => "Uh (as in Jonah)",
"age" => 90,
"armor_size" => "medium",
"greatest_fear" => "whales"
})
puts "First Query"
pp db.find({"first_name" => "Joan"})
puts "Second Query"
pp db.find({"age" => { "$lt" => 25 } })
puts "Third Query"
pp db.find({"armor_size" => { "$exists" => true } })which would output:
First Query
[{"first_name"=>"Joan",
"last_name"=>"Of Arc",
"age"=>15,
"armor_size"=>"small",
"id"=>0},
{"first_name"=>"Joan",
"last_name"=>"From Madmen",
"age"=>30,
"lipstick_color"=>"red",
"id"=>1},
{"first_name"=>"Joan",
"last_name"=>"Uh (as in Jonah)",
"age"=>90,
"armor_size"=>"medium",
"greatest_fear"=>"whales",
"id"=>2}]
Second Query
[{"first_name"=>"Joan",
"last_name"=>"Of Arc",
"age"=>15,
"armor_size"=>"small",
"id"=>0}]
Third Query
[{"first_name"=>"Joan",
"last_name"=>"Of Arc",
"age"=>15,
"armor_size"=>"small",
"id"=>0},
{"first_name"=>"Joan",
"last_name"=>"Uh (as in Jonah)",
"age"=>90,
"armor_size"=>"medium",
"greatest_fear"=>"whales",
"id"=>2}]
Documentation would be good. I haven't used it very extensively yet, so the next goal is to work out the bugs I must have created.
Look at MongoDB Query Language. Not everything is supported yet. For now I'll document the implemented features by pasting the Rspec -f doc output
rspec -f doc spec/mongolitedb_spec.rb
MongoLiteDB
should initialize db file
when using a single object
should allow insertion
should allow retrieval
should allow update
should allow deletion
insert
should add an id to record
should accept duplicate entries
should autoincrement id on each insert
should make a copy of object on insert
should allow batch inserts
find
should support querying nested documents
should return empty set if nested documents do not exist
should support multiple keyword conditions
$or operator
should return entries that match either condition
should allow multiple conditions that are anded together
should allow nested $or
$nor operator
should return entries that do not match any of the conditions
$and operator
should return entries that match all of the conditions
$in operator
should return entries that match any of the values
$nin operator
should return entries that do not match given values
$exists operator
should return entries that have the field defined when true
should return entries that do not have the field defined when false
numerical operations
$gt
should return entries where field is greater than the value
$gte
should return entries where field is greater than or equal to the value
$lt
should return entries where field is less than the value
$lte
should return entries where field is less than or equal to the value
$ne
should return entries where field is not equal to the value
$mod
should entries where the field value divided by the divisor has the specified remainder