Key Management

Managing Keys

Redis provides several commands for inspecting and managing keys themselves — independent of their data type.

KEYS — Find Keys by Pattern

KEYS *              -- all keys
KEYS user:*         -- keys starting with "user:"
KEYS *:session      -- keys ending with ":session"
KEYS user:?         -- keys matching single character after "user:"

Pattern wildcards:

• * — matches any number of characters
• ? — matches exactly one character
• [abc] — matches one character from the set

Warning: KEYS blocks the server while scanning all keys. Use SCAN in production.

TYPE — Get Data Type

SET mystr "hello"
RPUSH mylist "a" "b"
SADD myset "x" "y"
HSET myhash f1 v1

TYPE mystr     -- string
TYPE mylist    -- list
TYPE myset     -- set
TYPE myhash    -- hash

RENAME — Rename a Key

SET old_name "value"
RENAME old_name new_name
GET new_name    -- "value"
EXISTS old_name -- 0

If the new key already exists, it is overwritten.

DEL — Delete Multiple Keys

DEL key1 key2 key3    -- returns count of deleted keys

EXISTS — Check Multiple Keys

SET a "1"
SET b "2"
EXISTS a b c    -- 2 (a and b exist, c does not)

Note: EXISTS counts occurrences — if you pass the same key twice, it counts twice.

COPY — Copy a Key

SET source "original"
COPY source destination
GET destination    -- "original"

Returns 1 if copied, 0 if destination already exists.

OBJECT ENCODING — Internal Representation

SET num 42
OBJECT ENCODING num    -- "int"

SET short "hello"
OBJECT ENCODING short  -- "embstr"

Your Task

Set three keys: user:1 → "Alice", user:2 → "Bob", product:1 → "Laptop". Then use KEYS user:* to find only user keys.