LWT example

CREATE KEYSPACE mykeyspace WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '1'}  AND durable_writes = true;
USE mykeyspace;
CREATE TABLE tbl (
    k int,
    v int,
    x int,
    PRIMARY KEY (k,v)
);
INSERT INTO tbl (k,v,x) VALUES (1,2,0);
INSERT INTO tbl (k,v,x) VALUES (1,2,3) IF NOT EXISTS;
INSERT INTO tbl (k,v,x) VALUES (1,3,3) IF NOT EXISTS;