New in version 3.4.
Starting in version 3.4, MongoDB adds support for creating read-only views from existing collections or other views.
To create or define a view, MongoDB 3.4 introduces:
or if specifying a default collation for the view:
You must create views in the same database as the source collection.
Views exhibit the following behavior:
Views are read-only; write operations on views will error.
The following read operations can support views:
Views use the indexes of the underlying collection.
As the indexes are on the underlying collection, you cannot create, drop or re-build indexes on the view directly nor get a list of indexes on the view.
You cannot specify a
$naturalsort on a view.
For example, the following operation is invalid:
You cannot rename views.
- Views are computed on demand during read operations, and MongoDB executes read operations on views as part of the underlying aggregation pipeline. As such, views do not support operations such as:
- If the aggregation pipeline used to create the view suppresses the
_idfield, documents in the view do not have the
- You can specify a default collation for a view at creation time. If no collation is specified, the view’s default collation is the “simple” binary comparison collator. That is, the view does not inherit the collection’s default collation.
- String comparisons on the view use the view’s default collation. An operation that attempts to change or override a view’s default collation will fail with an error.
- If creating a view from another view, you cannot specify a collation that differs from the source view’s collation.
- If performing an aggregation that involves multiple views, such as with
$graphLookup, the views must have the same collation.
The view definition is public; i.e.
explain operations on the view will include the pipeline that defines the view. As such, avoid referring directly to sensitive fields and values in view definitions.
To remove a view, use the
db.collection.drop() method on the view.
You can modify a view either by dropping and recreating the view or using the
The following operations provide support for views, except for the restrictions mentioned in this page: