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Casson is a ODM (Object Data Model) for Apache Cassandra using native CQL protocol.

The main goal is to make it simple to use, take advantage of the power of Cassandra cluster, and allow the more sophisticated capabilities of Cassandra to be available. The secondary goal to have high performance (necessary for real-time work we do) without too much sanity checking. Now we have an opportunity to start with a completely asynchronous package. It may help to easily transition to Cassandra and Node.js combination.

Getting Started

Pool is the entry point for casson. It maintains connections to a host or a cluster of hosts and has a KeySpace in which it operates. Although KeySpace can be created, Pool only sets up connections to use a KeySpace.

Here is a simple way to set a couple of connections to a local Cassandra. It assumes that we have the KeySpace already in Cassandra and have done: npm install casson.

var casson = require('casson');

var pool = new casson.Pool({hosts    : ['localhost:9042'],
                            keyspace : 'casson_getstarted_ks',
                            username : 'u_getstarted',
                            password : 'pw_getstarted' });

With a pool in place, let's create a few tables:

var t1 = new casson.Table.construct(
  'T1', { 'a' : 3, 'b' : 'a string',
          '_PRIMARY_KEYS' : [ 'a', 'b' ] });
var t2 = new casson.Table.construct(
  'T2', { 'a' : 1, 'b' : [ 1 ], 'c' : { 'a': 'str'},
          '_PRIMARY_KEYS' : [ 'a' ]});

And there are good reasons to not have implicit id as the primary key. We can also add columns the old fashion way:

t1.c = 3.1415926;

The data types are derived from the values, and we have the option to change the defaults. Please note that b is the clustering key for t1.

Let's have the tables in Cassandra:


We can have asynchrouse callback as an optional argument to sendQuery.

Tables need data:

var i1 = new casson.Query.Insert(t1, { 'a' : 1, 'b' : 'foo' });
var i2 = new casson.Query.Insert('T1', { 'a' : 2, 'b' : 'bar', 'c' : 3.1 });
var i3 = new casson.Query.Insert(t2, { 'a' : 3, 'b' : [ 2, 3, 4, 5 ],
                                       'c' : { 'p' : 'some', 'q' : 'string' }});
var i4 = new casson.Query.Insert('T2', { 'a' : 4, 'b' : [ 2222, 44444 ],
                                         'c' : { 'p' : 'another', 'q' : 'one' }});


So the javascript smoothly maps to the cassandra types, inlcuding collection types like List and Map.

Did we forget something in first the List:

var u = new casson.Query.Update(t2, {'b' : {'list+' : [6]}}).where({'a' : 3});

With data in tables, there is a demand for queries:

var s1 = new casson.Query.Select(t1).where({'a' : 1});
  pool.sendQuery(s1, function(err, result) {

// result: { c : null, b : foo, a : 1 }

var s2 = new casson.Query.Select(t2, ['a', 'c']);
  pool.sendQuery(s2, function(err, result) {
}, null, true);

// result: [ [ 4, { p: 'another', q: 'one' } ],
//           [ 3, { p: 'some', q: 'string' } ] ]

The example directory has the cql and js. There are some timeouts to deal with the some of the setup delays.

Isn't it tempting to think what else is possible. Of course, the detailed API should have the answer. In case it doesn't, let's use the Wiki to communicate concerns of general interest.


API Documentation

It might be useful to browse the API documentation for further clarification. Casson API is the place to go.

Cassandra Documentation

Of course, to really take advantage of casson, it would be a really good idea to a take a look at Cassandra documentation.


Related software

They are also sources of good ideas and inspiration.

  • helenus a sophisticated CQL implementation with thrift

  • cql-protocol: a basic CQL binary protocol handling

  • python-cql: I like Python and also this one.


It works well for our purpose. In order to make it available for general use, however, a few things we don't actively use had to be included along with a few changes.

We can use Issues and Wiki section to get the process going for now.

To Do

  • Implement Batch CQL command.


Currently, I wrote this to do what we need to do, but it would be delightful when others make it better.


casson is distributed with Apache License, Version 2.0.