If you have missing shard key fields, you can set the shard key field to
null. If you want to set the missing shard key field to a
non-null value, see Change a Document's Shard Key Value.
To perform the update, you can use the following operations on a
mongos:
| | |
|---|
| | Can be used to set the missing key value to null only. Can be performed inside or outside a transaction. Can be performed as a retryable write or not. For additional requirements, refer to the specific
command/method.
|
| | Can be used to set the missing key value to null or any
other value. The update to set missing shard key fields must meet one of
the following requirements: the filter of the query contains an equality condition on the full
shard key in the query the filter of the query contains an exact match on _id the update targets a single shard
To set to a non-null value, refer to
Change a Document's Shard Key Value. For additional requirements, refer to the specific
command/method.
|
| | Can be used to set the missing key value to null or any
other value. When setting missing shard key fields with a method that
explicitly updates only one document, the update must meet
one of the following requirements: the filter of the query contains an equality condition on
the full shard key in the query the filter of the query contains an exact match on _id the update targets a single shard
Missing key values are returned when matching on null. To
avoid updating a key value that is null, include additional
query conditions as appropriate. To set to a non-null value, refer to
Change a Document's Shard Key Value. For additional requirements, refer to the specific
command/method.
|
| | To set to a null value, you can specify multiple shard
key modifications in the bulk operation. When setting missing shard key fields with a method that
explicitly updates only one document, the update must meet
one of the following requirements: the filter of the query contains an equality condition on
the full shard key in the query the filter of the query contains an exact match on _id the update targets a single shard
To set to a non-null value, refer to
Change a Document's Shard Key Value. For additional requirements, refer to the underlying
command/method.
|
Consider a sales collection which is sharded on the location
field. Some documents in the collection have no location field. A
missing field is considered the same as a null value for the field. To
explicitly set these fields to null, run the following command:
| db.sales.updateOne( |
| { _id: 12345, location: null }, |
| { $set: { location: null } } |
| ) |
When setting missing shard key fields with
db.collection.updateOne() or another method that explicitly
updates only one document, the update must meet one of the following
requirements:
the filter of the query contains an equality condition on the full
shard key in the query
the filter of the query contains an exact match on _id
the update targets a single Shard