[MongoDB] Update Operators | 수정 연산자

Update Operators

수정 연산자

- Update Operator는 DB에 저장된 데이터를 수정하거나 새로운 데이터를 추가할 수 있게 하는 연산자이다.
- MongoDB 5.0 버전부터, 수정 연산자는
  Document의 Field 이름이 string Type인 경우 Lexicographic Order(사전순)로 처리하고,
  numeric Type인 경우 Numeric Order(수치순)로 처리한다.

Example. MongoDB 5.0 vs Earlier

{ $set: { "a.2": <new value>, "a.10": <new value>, } }

MongoDB 5.0 : "a.2" 필드를 먼저 처리한다. (Numeric Order상, 2가 10보다 먼저이기 때문이다.)
MongoDB Earlier : "a.10" 필드를 먼저 처리한다. (Lexicographic Order(상, 1이 2보다 먼저이기 때문이다.)

 

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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.

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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.

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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.

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Bitwise

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

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Reference: MongoDB Documentation (URL)