Does CQL3 require a schema for Cassandra now?

Question

I\'ve just had a crash course of Cassandra over the last week and went from Thrift API to CQL to grokking SuperColumns to learning I shouldn\'t use them and user Composite Keys

Answer 1

I suggest you to explore composite columns with "WITH COMPACT STORAGE". A "COMPACT STORAGE" column family allows you to practically only define key columns:

Example:

CREATE TABLE entities_cargo ( entity_id ascii, item_id ascii, qt ascii, PRIMARY KEY (entity_id, item_id) ) WITH COMPACT STORAGE

Actually, when you insert different values from itemid, you dont add a row with entity_id,item_id and qt, but you add a column with name (item_id content) and value (qt content). So:

insert into entities_cargo (entity_id,item_id,qt) values(100,'oggetto 1',3);

insert into entities_cargo (entity_id,item_id,qt) values(100,'oggetto 2',3);

Now, here is how you see this rows in CQL3:

cqlsh:goh_master> select * from entities_cargo where entity_id = 100;

entity_id | item_id | qt

-----------+-----------+----

  100 | oggetto 1 |  3

  100 | oggetto 2 |  3

And how they are if you check tnem from cli:

[default@goh_master] get entities_cargo[100];

=> (column=oggetto 1, value=3, timestamp=1349853780838000)

=> (column=oggetto 2, value=3, timestamp=1349853784172000)

Returned 2 results.

You can access a single column with

select * from entities_cargo where entity_id = 100 and item_id = 'oggetto 1';

Hope it helps