Cassandra has no null. So in this context setting a column to null or
updating null is a delete. I think. I remember debating the semantics of
null once.
On Tuesday, February 18, 2014, Katsutoshi <nagapad.0...@gmail.com> wrote:
> Hi.
>
> I am using Cassandra 2.0.5 version. If null is explicitly set to a
column, paging_state will not work. My test procedure is as follows:
>
> ------
> create a table and insert 10 records using cqlsh. the query is as follows:
>
> cqlsh:test> CREATE TABLE mytable (id int, range int, value text,
PRIMARY KEY (id, range));
> cqlsh:test> INSERT INTO mytable (id, range) VALUES (0, 0);
> cqlsh:test> INSERT INTO mytable (id, range) VALUES (0, 1);
> cqlsh:test> INSERT INTO mytable (id, range) VALUES (0, 2);
> cqlsh:test> INSERT INTO mytable (id, range) VALUES (0, 3);
> cqlsh:test> INSERT INTO mytable (id, range) VALUES (0, 4);
> cqlsh:test> INSERT INTO mytable (id, range, value) VALUES (0, 5,
null);
> cqlsh:test> INSERT INTO mytable (id, range, value) VALUES (0, 6,
null);
> cqlsh:test> INSERT INTO mytable (id, range, value) VALUES (0, 7,
null);
> cqlsh:test> INSERT INTO mytable (id, range, value) VALUES (0, 8,
null);
> cqlsh:test> INSERT INTO mytable (id, range, value) VALUES (0, 9,
null);
>
> select data using datastax driver. the pseudocode is as follows:
>
> Statement statement =
QueryBuilder.select().from("mytable").setFetchSize(1);
> ResultSet rs = session.execute(statement);
> for(Row row : rs){
> System.out.println(String.format("id=%s, range=%s, value=%s",
> row.getInt("id"), row.getInt("range"),
row.getString("value")));
> }
>
> the result is as follows:
>
> id=0, range=0, value=null
> id=0, range=1, value=null
> id=0, range=2, value=null
> id=0, range=3, value=null
> id=0, range=4, value=null
> id=0, range=5, value=null
> id=0, range=7, value=null
> id=0, range=9, value=null
> ------
>
> Result is 8 records although 10 records were expected. Does anyone has a
similar issue?
>
> Thanks,
> Katsutoshi
>
--
Sorry this was sent from mobile. Will do less grammar and spell check than
usual.
