`drop`

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Syntax

Parameters
Output
Examples
Drop Collections Examples
Drop Views Example
Troubleshoot Errors

The drop command removes the specified collection or view from the federated database instance storage configuration. Use the wildcard "*" to remove all collections generated by the wildcard collection function (that is, collectionName()), including the wildcard collection rule itself. You cannot individually remove collections generated by the wildcard collection function.

Syntax

db.runCommand({ "drop" : "<collection-name|*>" })

db.runCommand({ "drop" : "<view-name>" })

Parameters

Parameter	Type	Description	Required?
`<collection-name>`	string	The name of the collection to drop or the wildcard `""` . You can specify the wildcard `""` to drop: All collections generated by the wildcard collection function `collectionName()` The wildcard collection rule	yes

Parameter	Type	Description	Required?
`<view-name>`	string	The name of the view to drop.	yes

Output

The command prints the following output if it succeeds. You can verify the results by running the show collections command. If the command fails, see Troubleshoot Errors for recommended solutions.

{ "ok" : 1, "ns" : "<database>.<collection>", "nIndexesWas" : 0 }

where:

ns reflects the collection namespace, which includes the database name, the dot (.) separator, and the collection name. For example: <database>.<collection>.
nIndexesWas reflects the number of indexes, the value of which is always 0 on Data Federation.

The command prints the following output if it succeeds. You can verify the results by running the storageGetConfig command. If the command fails, see Troubleshoot Errors for recommended solutions.

{ "ok" : 1, "ns" : "<database>.<view>", "nIndexesWas" : 0 }

where:

ns reflects the view namespace, which includes the database name, the dot (.) separator, and the view name. For example: <database>.<view>.
nIndexesWas reflects the number of indexes, the value of which is always 0 on Data Federation.

Examples

Drop Collections Examples

The following examples use the drop command to remove sample collections that were mapped to the sample dataset, airbnb and weather, in the AWS S3 store.

Basic Example

The following example uses the drop command to remove a sample collection named airbnb in a database named sample in the storage configuration.

use sample
db.runCommand({ "drop" : "airbnb"})

The previous command prints the following output:

{ "ok" : 1, "ns" : "sample.airbnb", "nIndexesWas" : 0 }

Wildcard Example

The following example uses the drop command to remove the wildcard collection function (collectionName()) and all collections created by the wildcard collection function in a database named sample in the storage configuration.

use sample
db.runCommand ({ "drop" : "*" })

The previous command prints the following output:

{ "ok" : 1, "ns" : "sample.*", "nIndexesWas" : 0 }

Drop Views Example

The following command removes a view named "listings" on the airbnb collection in the sample database:

use sample
db.runCommand({ "drop" : "listings" })

The previous command returns the following output:

Example

{ "ok" : 1, "ns" : "sample.listings", "nIndexesWas" : 0 }

Troubleshoot Errors

If the command fails, it returns one of the following errors.

Reason: Namespace (database, collection, or view) does not exist.

{
   ok: 0,
   errmsg: "ns not found",
   code: 26,
   codeName: "NamespaceNotFound"
}

Solution: Ensure that the namespace specified in the command is valid and exists in the storage configuration. If necessary, use the getStorageConfig command to retrieve the list of valid databases, collections, and views in the storage configuration.

Reason: Attempting to remove a collection created by the wildcard collection function (collectionName()).

{
   ok: 0,
   errmsg: "cannot drop a collection created from a wildcard",
   code: 26,
   codeName: "NamespaceNotFound"
}

Solution: Ensure that the collection you are dropping is not an individual collection dynamically generated by the wildcard collection function (collectionName()). Data Federation does not support dropping individual collections generated by the wildcard collection function.

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