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Description

This error signifies that a database command or operation was attempted on a MongoDB view, but the specific command is not supported for views. Views are read-only and do not permit operations that modify data, create indexes, or alter the database structure.

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Error Message

Command Not Supported On View

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Known Causes

4 known causes

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Attempting Write Operations

This error occurs when a command designed to insert, update, or delete data is executed against a view, which is inherently read-only.

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Using Unsupported Aggregation Stages

Certain aggregation pipeline stages, such as '$out' or '$merge', are not permitted on views as they attempt to write data or create new collections.

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Index Management Operations

Views do not have their own indexes. Attempting to create, drop, or manage indexes directly on a view will result in this error.

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Schema Modification Commands

Commands that alter the schema or structure of a collection, such as 'collMod' or renaming, cannot be applied to a view.

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Solutions

3 solutions available

1. Execute Command on Underlying Collection easy

Modify your operation to target the collection the view is based on, not the view itself.

1

Identify the underlying collection(s) used to define the view. You can find this information in the view's definition.

db.getCollectionInfos({ name: 'yourViewName' })

2

Rewrite your command (e.g., `aggregate`, `find`, `update`, `delete`, `count`) to operate directly on the identified underlying collection(s) instead of the view.

// Instead of:
db.yourViewName.aggregate([...])

// Use:
db.yourUnderlyingCollection.aggregate([...])

2. Adapt Aggregation Pipeline for View Limitations medium

Adjust your aggregation pipeline to exclude stages not supported on views.

1

Review the MongoDB documentation for aggregation pipeline stages that are supported on views. Common unsupported stages include `$merge`, `$out`, and certain administrative commands.

2

If your pipeline uses unsupported stages, consider alternative approaches. For example, instead of `$merge` or `$out` to write to another collection, you might need to perform that operation separately on the underlying collection after fetching data from the view.

// Example: If you were trying to use $merge on a view to create a new collection
// This is not supported on views. Instead, fetch data and then insert/update into a collection.
const dataFromView = db.yourViewName.aggregate([...]);
db.yourNewCollection.insertMany(dataFromView);

3

If the unsupported stage is crucial for your logic, you may need to rethink the view's purpose or your overall data processing strategy.

3. Use a Temporary Collection for Complex Operations medium

Materialize view data into a temporary collection to perform unsupported operations.

1

Create a temporary collection to hold the results of your view query.

db.createCollection('tempViewResults')

2

Populate the temporary collection with data from the view. This will likely involve an `aggregate` command on the view.

const viewData = db.yourViewName.aggregate([...]);
db.tempViewResults.insertMany(viewData);

3

Perform your unsupported command (e.g., `$merge`, `$out`) on the temporary collection.

db.tempViewResults.aggregate([
  { $match: { /* your conditions */ } },
  { $merge: { into: 'anotherCollection', on: '_id', whenMatched: 'replace', whenNotMatched: 'insert' } }
])

4

Optionally, drop the temporary collection once the operation is complete.

db.tempViewResults.drop()

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Related Errors

5 related errors

MongoDB Error 166: Command Not Supported On View