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 readingIn 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.
In Redis, the MSET command allows us to set multiple keys at once. It replaces any existing values, just as SET does.
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).
In Redis, the GET command returns the value of a given key. If the key doesn’t exist, it returns nil.
An error is returned if the value stored at key is not a string.
In MariaDB, you can use the SUBSTRING_INDEX() function to return everything before or after a certain character (or characters) in a string.
If you have a MongoDB collection with dates stored as strings, you can convert those into the Date BSON type if required.
Below are three ways to convert a string into a Date in MongoDB.
Continue readingMongoDB has a Date BSON type that allows you to store dates as dates.
You can also store dates as strings, if that’s what you need.
Taking it a step further, you can also convert a Date to a string.
This article presents three ways to convert a Date to a string in MongoDB.
Continue readingMongoDB 4.4 introduced nine new aggregation pipeline operators, including two new operators for finding and replacing a substring.
The two new operators that allow you to find and replace a substring are the $replaceOne and $replaceAll operators.
SQLite doesn’t have a concat() function like many other database management systems, such as SQL Server’s concat() and MySQL’s concat().
However, that doesn’t mean you can’t concatenate two strings in SQLite.
SQLite has a concatenation operator (||) that you can use to concatenate two strings.