🎁 Use unique index for UPDATE and DELETE

[BevanR]

Feature request; Support UNIQUE INDEX columns in the WHERE clause for UPDATE and DELETE queries.

E.g. It would be nice if UPDATE mydata SET value = 'orange' WHERE id = ? worked in the following scenario;

cqlsh:tmp_unique_index> describe mydata

CREATE TABLE tmp_unique_index.mydata (
    org text,
    id uuid,
    value text,
    PRIMARY KEY (org, id)
) WITH CLUSTERING ORDER BY (id ASC)
    AND default_time_to_live = 0
    AND transactions = {'enabled': 'true'};
CREATE UNIQUE INDEX mydata_id_index ON tmp_unique_index.mydata (id) INCLUDE (org)
    WITH transactions = {'enabled': 'true'};

cqlsh:tmp_unique_index> select * from mydata;

 org  | id                                   | value
------+--------------------------------------+------------
 ogre | 2db15f5b-c8ab-4788-955e-14e32feaf218 |      apple
 ogre | 70b99c4e-1ab7-4d39-a1a6-027cd2225f14 | watermelon
 acme | 10602fdc-65fa-4bcb-b1bd-d5ad686cfca9 |      apple
 acme | 3398ef74-6014-4a3a-9bb4-0f3da54e3456 |     banana

(4 rows)
cqlsh:tmp_unique_index> UPDATE mydata SET value = 'orange' WHERE id = 70b99c4e-1ab7-4d39-a1a6-027cd2225f14;
SyntaxException: Query error: Invalid CQL Statement. Missing condition on key columns in WHERE clause
UPDATE mydata SET value = 'orange' WHERE id = 70b99c4e-1ab7-4d39-a1a6-027cd2225f14;
                                         ^^
 (error -12)
cqlsh:tmp_unique_index> UPDATE mydata SET value = 'orange' WHERE id = uuid();
SyntaxException: Query error: Invalid CQL Statement. Missing condition on key columns in WHERE clause
UPDATE mydata SET value = 'orange' WHERE id = uuid();
                                         ^^
 (error -12)

However what should happen in case of UPDATE mydata SET value = 'orange' WHERE id = uuid()?