发布于 2015-09-14 14:56:06 | 171 次阅读 | 评论: 0 | 来源: 网络整理
The remove method removes documents from a collection.
The remove() method can take the following parameters:
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注解
You cannot use the remove() method with a capped collection.
Consider the following examples of the remove method.
To remove all documents in a collection, call the remove method with no parameters:
db.products.remove()
This operation will remove all the documents from the collection products.
To remove the documents that match a deletion criteria, call the remove method with the query criteria:
db.products.remove( { qty: { $gt: 20 } } )
This operation removes all the documents from the collection products where qty is greater than 20.
To remove the first document that match a deletion criteria, call the remove method with the query criteria and the justOne parameter set to true or 1:
db.products.remove( { qty: { $gt: 20 } }, true )
This operation removes all the documents from the collection products where qty is greater than 20.
注解
If the query argument to the remove() method matches multiple documents in the collection, the delete operation may interleave with other write operations to that collection. For an unsharded collection, you have the option to override this behavior with the $isolated isolation operator, effectively isolating the delete operation and blocking other write operations during the delete. To isolate the query, include $isolated: 1 in the query parameter as in the following example:
db.products.remove( { qty: { $gt: 20 }, $isolated: 1 } )