How do you multiply in MongoDB?

How do you multiply in MongoDB?

Multiplies numbers together and returns the result. Pass the arguments to $multiply in an array. The $multiply expression has the following syntax: { $multiply: [ , , ] }

What is $MUL in MongoDB?

MongoDB – Multiply Operator ($mul) This operator is used to multiply the value of the field by a number. $mul operator only updates those fields whose value are of numeric type like int, float, etc.

How do I count records in MongoDB?

MongoDB: db. collection. count() method

  1. db. collection.
  2. Example: Count all document from the collection. Count the number of the documents in the restaurants collection.
  3. Example : Count all Documents that Match a Query.
  4. Example : Count all Documents that Match a Query using more than on criteria.
  5. Behavior.

How do I round in MongoDB?

If resolves to a positive integer, $round rounds to decimal places. For example, $round : [1234.5678, 2] rounds to two decimal places and returns 1234.57 . If resolves to a negative integer, $round rounds using the digit to the left of the decimal.

What is $project in MongoDB?

Definition. $project. Passes along the documents with the requested fields to the next stage in the pipeline. The specified fields can be existing fields from the input documents or newly computed fields.

How many documents can MongoDB hold?

If you specify a maximum number of documents for a capped collection using the max parameter to create, the limit must be less than 2^32 documents. If you do not specify a maximum number of documents when creating a capped collection, there is no limit on the number of documents.

How do I find the size of a collection in MongoDB?

5 Ways to Check the Size of a Collection in MongoDB

  1. The dataSize() Method. Probably the quickest and easiest way to check the size of a MongoDB collection is to use the db.
  2. The totalSize() Method. The db.
  3. The stats() Method.
  4. The collStats Command.
  5. The $bsonSize Operator.

What is NumberLong in Mongodb?

NumberLong. The mongo shell treats all numbers as floating-point values by default. The mongo shell provides the NumberLong() wrapper to handle 64-bit integers. The NumberLong() wrapper accepts the long as a string: NumberLong(“2090845886852”)

How do you create a projection in MongoDB?

In MongoDB, projection means selecting only the necessary data rather than selecting whole of the data of a document. If a document has 5 fields and you need to show only 3, then select only 3 fields from them.

When should I use aggregate in MongoDB?

You can use aggregation operations to:

  1. Group values from multiple documents together.
  2. Perform operations on the grouped data to return a single result.
  3. Analyze data changes over time.

How many writes per second can MongoDB handle?

MongoDB 80,000+ insertions per second.

What is the maximum size of MongoDB?

16 megabytes
The maximum BSON document size is 16 megabytes. The maximum document size helps ensure that a single document cannot use excessive amount of RAM or, during transmission, excessive amount of bandwidth. To store documents larger than the maximum size, MongoDB provides the GridFS API.