【MongoDB】Update Operators

Update Operators

Fields

Name	Description
$currentDate	Sets the value of a field to current date, either as a Date or a Timestamp.
$inc	Increments the value of the field by the specified amount.
$min	Only updates the field if the specified value is less than the existing field value.
$max	Only updates the field if the specified value is greater than the existing field value.
$mul	Multiplies the value of the field by the specified amount.
$rename	Renames a field.
$set	Sets the value of a field in a document.
$setOnInsert	Sets the value of a field if an update results in an insert of a document. Has no effect on update operations that modify existing documents.
$unset	Removes the specified field from a document.

Array

Operators

Name	Description
$	Acts as a placeholder to update the first element that matches the query condition.
$[]	Acts as a placeholder to update all elements in an array for the documents that match the query condition.
$[<identifier>]	Acts as a placeholder to update all elements that match the arrayFilters condition for the documents that match the query condition.
$addToSet	Adds elements to an array only if they do not already exist in the set.
$pop	Removes the first or last item of an array.
$pull	Removes all array elements that match a specified query.
$push	Adds an item to an array.
$pullAll	Removes all matching values from an array.

Modifiers

Name	Description
$each	Modifies the $push and $addToSet operators to append multiple items for array updates.
$position	Modifies the $push operator to specify the position in the array to add elements.
$slice	Modifies the $push operator to limit the size of updated arrays.
$sort	Modifies the $push operator to reorder documents stored in an array.

Bitwise

Name	Description
$bit	Performs bitwise AND, OR, and XOR updates of integer values.

 

参考：https://docs.mongodb.com/manual/reference/operator/update/