MongoDB mongorestore 和带有记录的现有集合
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MongoDB mongorestore and existing collection with records
提问by Simone Carletti
I need to import (restore) a collection generated with mongodumpinto an existing database and I'd like the records to be merged into the existing collection.
我需要将生成的集合导入（恢复）mongodump到现有数据库中，并且我希望将记录合并到现有集合中。
Does mongorestoremerge the records in the same collection or it will drop the existing collection before restoring the records?
是否mongorestore合并同一集合中的记录，或者在恢复记录之前会删除现有集合？
回答by Niels van der Rest
mongorestorewill only drop the existing collection if you use the --dropargument.
mongorestore如果您使用该--drop参数，则只会删除现有集合。
If you don't use --drop, all documents will be inserted into the existing collection, unless a document with the same _idalready exists. Documents with the same _idwill be skipped, they are not merged. So mongorestorewill never delete or modify any of the existing data by default.
如果您不使用--drop，则所有文档都将插入到现有集合中，除非_id已经存在相同的文档。相同的文件_id将被跳过，它们不会被合并。所以mongorestore默认情况下永远不会删除或修改任何现有数据。
