In MongoDB, the $multiply aggregation pipeline operator multiplies numbers together and returns the result.
To use the $multiply operator, pass the numbers to the operator in an array.
The arguments can be any valid expression, as long as they resolve to numbers.
Continue readingIn MongoDB, you can use the $subtract aggregation pipeline operator to subtract numbers and/or dates.
In MongoDB, the $add aggregation pipeline operator adds values together. Such values can be numbers, or they can be numbers and a date.
The $add operator accepts the values as arguments. The arguments can be any valid expression as long as they resolve to either all numbers or to numbers and a date.
In MongoDB, the $anyElementTrue aggregation pipeline operator evaluates an array as a set and returns true if any of the elements are true.
If none of the elements is true, then it returns false.
An array’s element is true if it’s not false, null, 0, or undefined.
In MongoDB, the $allElementsTrue aggregation pipeline operator evaluates an array as a set and returns true if no element in the array is false.
If the array contains an element that is false, then $allElementsTrue returns false.
An array’s element is true if it’s not false, null, 0, or undefined.
MongoDB provides many ways to insert documents into a collection.
Here are 5 ways to insert documents into a collection when using the mongo shell.
Continue readingIn MongoDB, you can rename a field when updating documents in a collection.
To rename a field, call the $rename operator with the current name of the field and the new name. This renames the field in all matching documents that have a field with that name.
MongoDB’s import utility – mongoimport – introduced a new parameter that allows you to import CSV data as an array.
The --useArrayIndexFields parameter interprets natural numbers in fields as array indexes when importing CSV or TSV files.
MongoDB 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.
MongoDB provides various ways to update a document. The method you use will depend on exactly how you want to perform the update.
This article presents 4 ways to update a document in MongoDB.
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