Ian In Redis, the LRANGE command returns the specified elements of the list stored at the specified key.
The command requires us to specify a start and stop position for the elements to return. These are zero based indexes, so 0 is the first element in the list.
We can specify -1 for the last element in the list.
In Redis, the LMPOP command pops one or more elements from the first non-empty list key from the list of provided key names.
The LMPOP command is similar to LPOP, except that it can accept multiple keys. It’s also similar to BLPOP (which accepts multiple keys), except that it can pop multiple elements (BLPOP can only pop one element).
A generated column is a database column whose value is an expression. Therefore, the value of the generated column is usually derived (for example, it could be derived from values in other columns).
Generated columns are also sometimes referred to as computed columns or virtual columns.
Creating a generated column in MariaDB is essentially the same as creating a normal column. The difference is that the definition of the generated column contains an expression that determines the column’s value.
In Redis, the BLMPOP command is the blocking variant of LMPOP.
Just like the LMPOP command, BLMPOP pops one or more elements from the first non-empty list key from the list of provided key names. However, unlike LMPOP, if all lists are empty, BLMPOP blocks the connection until another client pushes to it or until the timeout (a double value specifying the maximum number of seconds to block) elapses.
In Redis, the BRPOP command is the blocking variant of the RPOP command. It blocks the connection when there are no elements to pop from any of the given lists.
The way the command works is that an element is popped from the tail of the first list that is non-empty, with the given keys being checked in the order that they are given. When there are no elements to pop from any of the lists, it blocks the connection.
In Redis, the RPOP command removes and returns the last elements of the list stored at the specified key.
By default, the command pops a single element from the end of the list. However, we have the option of passing a second argument that specifies how many elements to pop.
In Redis, the BLPOP command is the blocking version of the LPOP command. It blocks the connection when there are no elements to pop from any of the given lists.
The way the command works is that an element is popped from the head of the first list that is non-empty, with the given keys being checked in the order that they are given. When there are no elements to pop from any of the lists, it blocks the connection.
In Redis, the LPOP command removes and returns the first elements of the list stored at the specified key.
By default, the command pops a single element from the beginning of the list. However, we have the option of passing a second argument that specifies how many elements to pop.
When using Redis, we often have many ways to do the same thing. One example of this is with deleting keys.
Below are four options for deleting keys in Redis.
In Redis, the RPUSHX command inserts one or more values into the tail of the list at the specified key, but only if the key exists and it contains a list.
If the key doesn’t exist, no operation is performed. If the key exists but it doesn’t contain a list, an error is returned.