In Redis, the DEL command removes one or more keys. If a specified key doesn’t exist, it’s ignored.
Tag: what is
Redis LCS Command Explained
In Redis, the LCS command implements the longest common subsequence algorithm.
The longest common subsequence algorithm finds the longest subsequence common to all sequences in a set of sequences. Note that this is different to the longest common string algorithm (also known as the longest common substring algorithm), which requires that matching characters in the string are contiguous. The longest common subsequence algorithm, on the other hand, doesn’t require matching characters to be contiguous.
The LCS command was introduced in Redis 7.0.0.
Continue readingRedis GETEX Command Explained
The Redis GETEX command enables us to get the value of a key, then set the key’s expiration. We can also use it to remove any existing expiration associated with the key.
How NVL2() Works in MariaDB
In MariaDB, the NVL2() function allows us to replace a value with another value, the new value being determined by whether or not the initial value is null.
It’s similar to the NVL() function, except that NVL2() accepts three arguments instead of two. This allows us to specify a different value to return in the event the first argument is not null.
Redis SETNX Command Explained
The Redis SETNX command sets a key to a given value, but only if the key doesn’t already exist. If the key already holds a value, no operation is performed.
Note: The SET command can do the same thing, and it’s possible that the SETNX command may be deprecated at some point. Therefore, it’s probably a good idea to use SET instead of SETNX if possible.
Redis MSETNX Command Explained
In Redis, the MSETNX command allows us to set multiple keys at once, but only if none of them exist.
This allows us to set multiple keys representing different fields of a single logical object in a way that ensures that either all the fields are set, or none are set.
Continue readingRedis MGET Command Explained
In Redis, the MGET command allows us to get the values of multiple keys at once. The values are returned in an array reply.
If a specified key doesn’t exist, MGET returns nil for that key.
Redis MSET Command Explained
In Redis, the MSET command allows us to set multiple keys at once. It replaces any existing values, just as SET does.
SQL Server CASE Statement
The SQL Server CASE statement evaluates a list of conditions and returns one of multiple possible result expressions.
Although it’s commonly known as the “CASE statement”, the SQL Server documentation lists it as an expression. Plus it’s referred to as the “CASE expression” in the SQL standard. Some other DBMSs distinguish between the CASE statement and the CASE expression. Either way, here’s a quick rundown on how the “CASE statement” (or CASE expression) works in SQL Server.
Redis SET Command Explained
In Redis, the SET command sets a key to hold a given string value.
If the key already holds a value, it is overwritten with the new value. Also, any previous time to live associated with the key is discarded (assuming a successful SET operation).