Keys, TTL & Data Types — Series 2

Preview — 3 of 10 questions

What does TYPE mykey return for a key created with LPUSH mykey 'a'?

javascript

LPUSH mylist "a"
TYPE mylist
"list"

A"list"

B"string"

C(integer) 1

DTYPE only works on String keys; it errors for List keys

What does RENAME oldkey newkey do if newkey already exists?

javascript

SET a "hello"
SET b "world"
RENAME a b
GET b
"hello"   -- b's original value ("world") is gone, silently overwritten
GET a
(nil)     -- a no longer exists

AIt fails with an error to avoid overwriting existing data

BIt renames oldkey to newkey, silently overwriting whatever value newkey previously held

CIt merges the values of both keys together

DIt creates a third key combining both names

What does APPEND mykey 'World' do if mykey currently holds 'Hello'?

javascript

SET greeting "Hello"
APPEND greeting "World"
(integer) 10   -- length of "HelloWorld"
GET greeting
"HelloWorld"

AIt returns an error because APPEND only works on empty keys

BIt replaces the value entirely with 'World'

CIt concatenates 'World' onto the existing value, making mykey equal to 'HelloWorld', and returns the new total string length

DIt creates a List with two elements: 'Hello' and 'World'

Answer all 10 questions (7 more), see explanations for every answer, and track your score.