30 Questions
What is the purpose of the updateOne() method in MongoDB?
Updates a single document that satisfies a filter
Which operator is used to increment a field by a specified value in MongoDB update operations?
$inc
What happens if the $inc operator is used on a field with a null value in MongoDB?
It generates an error
When using the updateMany() method in MongoDB, what does it do?
Updates all documents in the collection
In MongoDB, what is the purpose of the $set operator in update operations?
Updates existing fields with new values
How would you update the 'salary' field from 70000 to 85000 for documents in the 'employees' collection in MongoDB?
{ $set: { salary: 85000 } }
What does the $inc operator do in the 'db.updateopr.updateOne({_id:1}, {$inc:{qty:2}})' query?
Increase the qty field by 2
Which query decreases the quantity field by 2?
db.updateopr.updateOne({_id:1}, {$inc:{qty:-2}})
What is the purpose of the $rename operator in MongoDB update operations?
Updates the name of a field
How does the $rename operator handle conflicts when updating the name of a field?
Performs an $unset of both old and new names and then a $set operation with the new name
Which type of fields can the $rename operator rename using dot operator in MongoDB?
Fields in embedded documents
In MongoDB, what happens when the document already has a field with the new name while using the $rename operator?
$rename removes that field and renames the specified one
What does the $set operator do in MongoDB?
Replaces the value of a field with the specified value
In MongoDB, how does $set behave when specifying multiple field-value pairs?
Updates or creates each field
When using $set in MongoDB, what happens if the field being updated does not exist?
A new field is added with the specified value
How can you update a top-level field in MongoDB using the $set operator?
Use dot notation
What do you need to use to specify a field within an embedded document in MongoDB?
Dot notation
In MongoDB, how does $set behave when updating array elements?
It appends new elements without replacing existing ones
What does the $min operator do in MongoDB?
Updates the field to a specified value if the specified value is less than the current value
In MongoDB, what happens if the field does not exist when using the $min operator?
The field is set to the specified value
How does the $min operator treat existing fields when updating?
Updates only if the current value is less than the new value
When using $max in MongoDB, what does it do if the specified value is greater than the current value of the field?
Updates the field to the new value
What does the $max operator do when updating a field that does not exist?
Sets the field to a specified value
In MongoDB, what is the functionality of $max operator when comparing numbers?
Updates to a specified value if greater than current value
What happens when applying the $mul operator to a field that is not in the document?
The field is created and the value is set to zero
What is the syntax for applying the $mul operator to a field in an embedded document or array?
{ field: { $mul: value } }
If the price field has a value of 10.99 and the quantity field has a value of 25, what will be the result after applying $mul to these fields?
Price becomes 13.74, quantity becomes 50
What will be the type of the value in the 'price' field after using the $mul operator to multiply Decimal128(10) by Int32(5)?
Decimal128
What may happen when multiplying values of mixed numeric types using the $mul operator?
Conversion of numeric types may occur
What is the outcome if a document already contains a price field and the $mul operator is applied to it?
The existing price field will be updated with the new value
Learn how to use the $mul operator in MongoDB to multiply the value of a field by a number. Understand the syntax and considerations for updating or creating fields, including in embedded documents or arrays.
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