# create Event

ce-create## Summary

`create`
A `create` event occurs when a collection is created on a watched database and the change stream has the [showExpandedEvents](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/change-events/#std-label-change-streams-expanded-events) option set to `true`.

## Description

<table>
<tr>
<th id="Field">
Field

</th>
<th id="Type">
Type

</th>
<th id="Description">
Description

</th>
</tr>
<tr>
<td headers="Field">
`_id`

</td>
<td headers="Type">
Document

</td>
<td headers="Description">
A [BSON](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/glossary/#std-term-BSON) object, which serves as an identifier for the change stream event. This value is used as the `resumeToken` for the `resumeAfter` parameter when resuming a change stream. The fields within the `_id` object depend on the MongoDB versions and, in some cases, the [feature compatibility version (FCV)](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/command/setFeatureCompatibilityVersion/#std-label-view-fcv) at the time of the change stream's opening or resumption.

For an example of resuming a change stream by `resumeToken`, see [Resume a Change Stream](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/changeStreams/#std-label-change-stream-resume).

</td>
</tr>
<tr>
<td headers="Field">
`clusterTime`

</td>
<td headers="Type">
Timestamp

</td>
<td headers="Description">
`clusterTime` is the timestamp from the oplog entry associated with the event.

Due to [oplog size limits](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/core/transactions-production-consideration/#std-label-txn-oplog-size-limit), [multi-document transactions](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/core/transactions/#std-label-transactions) may create multiple oplog entries. In a transaction, change stream events staged in a given oplog entry share the same `clusterTime`.

Events with the same `clusterTime` may not all relate to the same transaction. Some events don't relate to a transaction at all. Starting in MongoDB 8.0, this may be true for events on any deployment. In previous versions, this behavior was possible only for events on a sharded cluster.

To identify events for a single transaction, you can use the combination of `lsid` and `txnNumber` in the change stream event document.

</td>
</tr>
<tr>
<td headers="Field">
`collectionUUID`

</td>
<td headers="Type">
UUID

</td>
<td headers="Description">
If the change occurred on a collection,  `collectionUUID` indicates the collection's UUID (Universally Unique Identifier). If the change occurred on a view, `collectionUUID` doesn't exist.

</td>
</tr>
<tr>
<td headers="Field">
`lsid`

</td>
<td headers="Type">
document

</td>
<td headers="Description">
The identifier for the session associated with the transaction.

Only present if the operation is part of a [multi-document transaction](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/core/transactions/).

</td>
</tr>
<tr>
<td headers="Field">
`ns`

</td>
<td headers="Type">
document

</td>
<td headers="Description">
The namespace (database and or collection) affected by the event.

</td>
</tr>
<tr>
<td headers="Field">
`ns.coll`

</td>
<td headers="Type">
string

</td>
<td headers="Description">
The name of the collection where the event occurred.

</td>
</tr>
<tr>
<td headers="Field">
`ns.db`

</td>
<td headers="Type">
string

</td>
<td headers="Description">
The name of the database where the event occurred.

</td>
</tr>
<tr>
<td headers="Field">
`nsType`

</td>
<td headers="Type">
string

</td>
<td headers="Description">
Shows the namespace type of the collection created by this event.

Indicates the event creates a collection.

Indicates the event creates a timeseries collection.

Indicates the event creates a non-timeseries view.

</td>
</tr>
<tr>
<td headers="Field">
`operationDescription`

</td>
<td headers="Type">
document

</td>
<td headers="Description">
Additional information on the change operation.

This document and its subfields only appears when the change stream uses [expanded events](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/change-events/#std-label-change-streams-expanded-events).

</td>
</tr>
<tr>
<td headers="Field">
`operationDescription.``idIndex`

</td>
<td headers="Type">
document

</td>
<td headers="Description">
The default `_id` index for a new collection.

</td>
</tr>
<tr>
<td headers="Field">
`operationType`

</td>
<td headers="Type">
string

</td>
<td headers="Description">
The type of operation that the change notification reports.

Returns a value of `create` for these change events.

</td>
</tr>
<tr>
<td headers="Field">
`txnNumber`

</td>
<td headers="Type">
NumberLong

</td>
<td headers="Description">
Together with the [lsid](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/change-events/create/#std-label--idref--lsid), a number that helps uniquely identify a transction.

Only present if the operation is part of a [multi-document transaction](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/core/transactions/).

</td>
</tr>
<tr>
<td headers="Field">
`wallTime`

</td>
<td headers="Type">
[ISODate](https://mongodbcom-cdn.staging.corp.mongodb.com/docs/reference/glossary/#std-term-ISODate)

</td>
<td headers="Description">
The server date and time of the database operation. `wallTime` differs from `clusterTime` in that `clusterTime` is a timestamp taken from the oplog entry associated with the database operation event.

</td>
</tr>
</table>

## Example

The following example shows a `create` event:

```json
{
   "_id": { <ResumeToken> },
   "operationType": "create",
   "clusterTime": Timestamp({ t: 1654894547, i: 24 }),
   "collectionUUID": UUID("98046a1a-b649-4e5b-9c75-67594221ce19"),
   "wallTime": ISODate("2022-06-10T20:55:47.947Z"),
   "ns": {
      "db": "test",
      "coll": "names"
   },
   "operationDescription": {
      "idIndex": { "v": 2, "key": { _id: 1 }, "name": "_id_" }
   }
}
```

