Caasandra PRIMARY KEY column "user" cannot be restricted as preceding column "eventtype" is not restricted

Question

The table i developed is below one

create table userevent(id uuid,eventtype text,sourceip text,user text,sessionid text,roleid int,menu text,action text,log text,date timestamp,PRIMARY KEY (id,eventtype,user));

 id                                   | eventtype | user    | action | date                     | log      | menu      | roleid | sessionid | sourceip
--------------------------------------+-----------+---------+--------+--------------------------+----------+-----------+--------+-----------+--------------
 b15c6780-d69e-11e8-bb9a-59dfa00365c6 |  DemoType |    Aqib |  Login | 2018-10-01 04:05:00+0000 |  demolog |  demomenu |      1 |    Demo_1 | 121.11.11.12
 95df3410-d69e-11e8-bb9a-59dfa00365c6 |  DemoType |    Aqib |  Login | 2018-09-30 22:35:00+0000 |  demolog |  demomenu |      1 |    Demo_1 | 121.11.11.12
 575b05c0-d69e-11e8-bb9a-59dfa00365c6 |  DemoType |    Aqib |  Login | 2018-10-01 04:05:00+0000 |  demolog |  demomenu |      1 |    Demo_1 | 121.11.11.12
 e6cbc190-d69e-11e8-bb9a-59dfa00365c6 | DemoType3 |   Jasim |  Login | 2018-05-31 22:35:00+0000 | demolog3 | demomenu3 |      3 |    Demo_3 | 121.11.11.12
 d66992a0-d69e-11e8-bb9a-59dfa00365c6 |  DemoType | Shafeer |  Login | 2018-07-31 22:35:00+0000 |  demolog |  demomenu |      2 |    Demo_2 | 121.11.11.12

But when i queried as below,

select * from userevent where user='Aqib'; 

Its showing some thing like this : InvalidRequest: Error from server: code=2200 [Invalid query] message="PRIMARY KEY column "user" cannot be restricted as preceding column "eventtype" is not restricted"

What is the error...........

Answer 1

You need to read about data modelling for Cassandra, or for example take DS220 course on the DataStax Academy. Every row has primary key consisting of the partition key that defines on which node the data is located, and clustering keys that define placement inside partition. In your case, your primary key consists at least from id, eventtype, user. To put condition on user you need to specify both id and eventtype.

You can add the index, or materialized view to access only by user, but I recommend to get more into data modelling first - define your queries, and then build table structures about queries that you need to perform.