If you’ve got a Redis hash with a field that needs to be deleted, you can use the HDEL command.
DBMS
Database Management Systems
Fix “ERR syntax error” when calling SRANDMEMBER in Redis
If you’re getting an error that reads “ERR syntax error” when calling the SRANDMEMBER command in Redis, it could be that you’re passing too many arguments.
To fix this issue, be sure to pass the correct number of arguments. At the time of writing, SRANDMEMBER accepts up to two arguments. Any more than this results in an error.
4 Ways to Insert a Field in a Redis Hash
I decided to compile a list of commands that can insert a new field into a Redis hash. Here are four options for inserting a new field into a Redis hash.
Redis HINCRBYFLOAT Command
The Redis HINCRBYFLOAT command increments the field in the hash at the specified key by a floating point number. We specify how much we want the field to increment by when we call the command.
Redis HINCRBY Command
The Redis HINCRBY command increments the number that’s stored at the specified field in the hash at the specified key. We specify how much we want the field to increment by when we call the command.
Redis HVALS Command
The Redis HVALS command returns all values in the hash stored at the specified key.
Redis HLEN Command
The Redis HLEN command returns the number of fields in the hash stored at the specified key.
Fix “WRONGTYPE Operation against a key holding the wrong kind of value” when using SMEMBERS in Redis
If you get an error that reads “WRONGTYPE Operation against a key holding the wrong kind of value” when using the SMEMBERS command in Redis, it’s probably because you’re passing a key with the wrong data type to the command.
The SMEMBERS command is a “set” command, and so it is intended to be used on keys that contain a set. If the key holds a different data type, you’ll likely get the above error.
Redis HGETALL Command
The Redis HGETALL command returns all fields and values from the hash at the specified key.
Redis HMGET Command
The Redis HMGET command allows us to get multiple values from a hash. It returns the value/s associated with the specified field/s in the hash at the specified key.