Database Management Systems
If you’re getting an error that reads “ERR wrong number of arguments for ‘spop’ command” in Redis, it’s because you’re calling the SPOP command with the wrong number of arguments.
At the time of writing, I find that I only get this argument when I pass no arguments. If I pass too many, I get a different error.
In any case, to fix this issue, be sure to pass at least one argument to the command (and at the time of writing, no more than two).
Continue readingHere are a couple of ways to check whether or not a key exists in Redis.
Continue readingRedis provides us with two commands that allow us to get one or more random members from a given set – SRANDMEMBER and SPOP.
Actually, the commands are slightly different in that one deletes the random member whereas the other doesn’t, and so the command you choose will depend on whether or not you want to delete the random member at the same time.
Continue readingIn SQLite, we can use the TIME() function to add a given number of hours to a time value.
If we’re dealing with datetime values, we can use the DATETIME() function.
If you’re getting an error that reads “ERR value is out of range, must be positive” in Redis, it’s probably because you’re passing a negative count value to the SPOP command.
To fix this issue, make sure the second argument (if supplied) is a positive value.
Continue readingIf you’re getting an error that reads “ERR wrong number of arguments for ‘sismember’ command” in Redis, it’s because you’re calling the SISMEMBER command with the wrong number of arguments.
To fix this issue, make sure you’re passing the correct number of arguments. At the time of writing, the correct number of arguments for this command is two.
Continue readingIn Redis, the SUNIONSTORE command does the same thing that SUNION does, except that it stores the result in a key. More specifically, it takes the members of the set resulting from the union of all of the given sets, and stores them in the specified key.
In Redis, the SUNION command returns the members of the set resulting from the union of all of the given sets.
Here are five ways to see whether a table contains a generated column in MariaDB.
Continue readingIn Redis, the SREM command allows us to remove one or more members from a set.