mongodb find with project
The examples in this tutorial use a collection inventory and use the db.collection.find() method in the mongo shell. The db.collection.find() method returns a .... For instance, you cannot project a portion of an array using the array index; e.g. "r,Note. For the _id field, you do not have to explicitly specify _id: 1 to return the _id field. The db.collection.find() method always returns the _id field unless you specify _id: 0 to suppress the field. A projection cannot contain both include and exclu
| 相關軟體 MongoDB 資訊 | |
|---|---|
 mongodb find with project 相關參考資料
Project Fields to Return from Query — MongoDB Manual 3.6
By default, queries in MongoDB return all fields in matching documents. To limit the amount of data that MongoDB sends to applications, you can include a projection document to specify or restrict fie... https://docs.mongodb.com Limit Fields to Return from a Query — MongoDB Manual 3.0
The examples in this tutorial use a collection inventory and use the db.collection.find() method in the mongo shell. The db.collection.find() method returns a .... For instance, you cannot project a p... https://docs.mongodb.com Project Fields to Return from Query — MongoDB Manual 3.2
Note. For the _id field, you do not have to explicitly specify _id: 1 to return the _id field. The db.collection.find() method always returns the _id field unless you specify _id: 0 to suppress the fi... https://docs.mongodb.com db.collection.find() — MongoDB Manual 3.6 - MongoDB Documentation
Parameter, Type, Description. query, document, Optional. Specifies selection filter using query operators. To return all documents in a collection, omit this parameter or pass an empty document ( } ).... https://docs.mongodb.com $project (aggregation) — MongoDB Manual 3.6
The $project stage has the following prototype form: copy. $project: <specification(s)> } }. The $project takes a document that can specify the inclusion of fields, the suppression of the _id ... https://docs.mongodb.com $ (projection) — MongoDB Manual 3.6 - MongoDB Documentation
The $elemMatch projection operator takes an explicit condition argument. This allows you to project based on a condition not in the query, or if you need to project based on multiple fields in the arr... https://docs.mongodb.com db.collection.findOne() — MongoDB Manual 3.6
Returns: One document that satisfies the criteria specified as the first argument to this method. If you specify a projection parameter, findOne() returns a document that only contains the projection ... https://docs.mongodb.com $filter (aggregation) — MongoDB Manual 3.6
Reference >; Operators >; Aggregation Pipeline Operators >; $filter (aggregation). $filter (aggregation)¶. On this page. Definition; Behavior; Example. Definition¶. $filter ¶. New in version ... https://docs.mongodb.com $elemMatch (projection) — MongoDB Manual 3.6
The $elemMatch projection operator takes an explicit condition argument. This allows you to project based on a condition not in the query, or if you need to project based on multiple fields in the arr... https://docs.mongodb.com projection - How to select a single field in MongoDB? - Stack Overflow
In the following operation, find() method returns all documents that match the query. In the result set, only ... In this example from the folks at Mongo, the returned documents will contain only the ... https://stackoverflow.com |