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From "Laing, Michael" <michael.la...@nytimes.com>
Subject Re: Help with select IN query in cassandra
Date Mon, 01 Sep 2014 00:32:37 GMT
Are event_time and timestamp essentially representing the same datetime?

On Sunday, August 31, 2014, Subodh Nijsure <subodh.nijsure@gmail.com> wrote:

> I have following database schema
>
> CREATE TABLE sensor_info_table (
>   asset_id text,
>   event_time timestamp,
>   "timestamp" timeuuid,
>   sensor_reading map<text, text>,
>   sensor_serial_number text,
>   sensor_type int,
>   PRIMARY KEY ((asset_id), event_time, "timestamp")
> );
>
> CREATE INDEX event_time_index ON sensor_info_table (event_time);
>
> CREATE INDEX timestamp_index ON sensor_info_table ("timestamp");
>
> Now I am able to insert the data into this table, however I am unable
> to do following query where I want to select items with specific
> timeuuid values.
>
> It gives me following error.
>
> SELECT * from mydb.sensor_info_table where timestamp IN (
> bfdfa614-3166-11e4-a61d-b888e30f5d17 ,
> bf4521ac-3166-11e4-87a3-b888e30f5d17) ;
>
> Bad Request: PRIMARY KEY column "timestamp" cannot be restricted
> (preceding column "event_time" is either not restricted or by a non-EQ
> relation)
>
> What do I have to do to make this work?
>
> For what its worth I am using django for my front end development and
> I am using "timestamp timeuuid" field as unique indentifier to
> reference specific sensor reading from django framework -- since
> cassandra doesn't have way to generate unique id upon insert (like
> old-style rdms's auto-fields).
>
>
> Below is software version info.
>
> show VERSION ; [cqlsh 4.1.1 | Cassandra 2.0.9 | CQL spec 3.1.1 |
> Thrift protocol 19.39.0]
>
> I really don't understand what the error message preceeding column
> "event_time" is either not restricted or by no-EQ relation?
>
> -Subodh Nijsure
>

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