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{ name: 'book', tags: { words: ['abc','123'], lat: 33, long: 22 } } Suppose this is a document. How do I remove "words" completely from all the documents in this collection? I want all documents to be without "words":
{ name: 'book', tags: { lat: 33, long: 22 } } 
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In MongoDB, you can use the $unset field update operator to completely remove a field from a document. The $unset operator is designed specifically to delete a field and its value from the document.
Delete a field from a table. In the Navigation Pane, right-click the table, and then click Design View. In the table design grid, select the field that you want to delete, and then press DEL.
To remove an element, update, and use $pull in MongoDB. The $pull operator removes from an existing array all instances of a value or values that match a specified condition.
To delete all documents in a collection, pass an empty document ( {} ). Optional. To limit the deletion to just one document, set to true . Omit to use the default value of false and delete all documents matching the deletion criteria.
Try this: If your collection was 'example'
db.example.update({}, {$unset: {words:1}}, false, true); Refer this:
http://www.mongodb.org/display/DOCS/Updating#Updating-%24unset
UPDATE:
The above link no longer covers '$unset'ing. Be sure to add {multi: true} if you want to remove this field from all of the documents in the collection; otherwise, it will only remove it from the first document it finds that matches. See this for updated documentation:
https://docs.mongodb.com/manual/reference/operator/update/unset/
Example:
db.example.update({}, {$unset: {words:1}} , {multi: true}); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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