The HGET
command is used in Redis to retrieve the value associated with a specified field in a hash stored at a key. A common use case for HGET
might involve storing user attributes (name, email, etc.) as fields in a hash structure with the user ID as the key.
Here's how you could use HGET
with the redis-rb library in Ruby:
require 'redis' redis = Redis.new # Set user details user_id = "1" redis.hset(user_id, "name", "John Doe") redis.hset(user_id, "email", "john.doe@example.com") # Get a specific attribute (name) of the user name = redis.hget(user_id, "name") puts name # Outputs: John Doe
In this example, we first create a new Redis instance. Then, we use hset
to add two fields ("name" and "email") to the hash identified by a user_id
. Afterwards, we use hget
to retrieve the "name" field from the hash.
hget
. If the provided key doesn't exist or if it is not a hash, Redis will return a nil object. Always check for nil before trying to use the returned value.hget
on a non-existing key?If you try to use hget
on a non-existing key, Redis will just return nil. It won't raise an error.
Yes, you can do so using the hmget
command, which takes multiple field names and returns all their corresponding values.
Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.