How can i list Cassandra cql result? Do i have to parse JSON?

Question

How can i parse my json style result from Cassandra? I'm using the cassandra-cql gem for rails and i want to parse the query result to list all messages. My query looks like:

def self.get_messages uid
  @@db.execute("SELECT * FROM messages WHERE uid=?", uid)
end

how can i list all messages? My current view is:

<% json_dec = ActiveSupport::JSON.decode(u.row.to_json) %>
<% json_dec.each do |f| %>
  <%= f[1] %><br/>
<%end%>

and it returns:

1
[{"name"=>"uid", "value"=>"1", "timestamp"=>-1}, {"name"=>"1326751801", "value"=>"test content", "timestamp"=>1326751801970000}, {"name"=>"1326754147", "value"=>"some content to test", "timestamp"=>1326754147612000}]

Is there any better way for the query? how do others solve this problem?

psanford · Accepted Answer · 2012-01-17T03:40:14.933

Encoding to json and the decoding again doesn't make much sense. Instead you can call #to_hash on the row object which will give you a hash of column_name => value. Then you could iterate over that:

<% row.to_hash.each do |key, value| %>
  <p>key: <%= key %>, value: <%= value %></p>
<%end%>

It also looks like you need to change your implementation of get_message to call fetch:

def self.get_messages uid
  @@db.execute("SELECT * FROM messages WHERE uid=?", uid).fetch
end

How can i list Cassandra cql result? Do i have to parse JSON?

1 Answers1