Update as the word describes, is used to change the values in an existing document in MongoDB. It can be done in 3 ways in MongoDB:
- updateOne()
- updateMany()
- replaceOne()
updateOne()
Syntax
updateOne( filter,data, options)
updateOne() is used to update the first document(from the top) that satisfies the parameters( filter, data, options).
- filter: This parameter sets the criteria to update a document.
- data: This includes the data that needs to be updated.
- options: This includes upsert, collation, writeConcern, and other options that we are going to discuss later.
Let's understand the concept of the updateOne() with the help of the example below:
Example
You have a collection named edatabase that contains the following 4 documents:
Now, you need to update the salary of those employees whose salary is <30000 by giving incrementation for 2000. Follow the code below for the same:
db.edatabase.updateOne( {Salary: {$lt: 30000}},{$inc:{Salary: 2000}})
In the above-mentioned code:
{Salary:{$lt: 30000}} is the filter applied. While {$inc:{Salary: 2000}} is the data part that displays what update we want to make in the values.
Output
The output says that two values are altered. Therefore, the final dataset is shown below wherein the salary below 30000 is incremented by 2000:
Note: the updateOne() command is responsible to update one document that satisfies the parameters first.