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How do you ensure consistency in MongoDB?
How does MongoDB ensure consistency? MongoDB is consistent by default: reads and writes are issued to the primary member of a replica set. Applications can optionally read from secondary replicas, where data is eventually consistent by default.
How do I stop MongoDB from inserting duplicate records?
To prevent MongoDB from inserting the same document more than once, create a unique index on the name field. With a unique index, if multiple applications issue the same update with upsert: true, exactly one update() would successfully insert a new document.
What is insert many in MongoDB?
The insertMany() method inserts one or more documents in the collection. It takes array of documents to insert in the collection. If you insert a document in the collection without _id field, then MongoDB will automatically add an _id field and assign it with a unique ObjectId.
How do I insert multiple rows in MongoDB?
insertMany() can insert multiple documents into a collection. Pass an array of documents to the method. The following example inserts three new documents into the inventory collection. If the documents do not specify an _id field, MongoDB adds the _id field with an ObjectId value to each document.
What happens if I insert one document in MongoDB?
Note that one document was inserted: The first document of _id: 13 will insert successfully, but the second insert will fail. This will also stop additional documents left in the queue from being inserted. With ordered to false, the insert operation would continue with any remaining documents.
How does the insertmany function work in mongod?
Given an array of documents, insertMany() inserts each document in the array into the collection. By default documents are inserted in order. If ordered is set to false, documents are inserted in an unordered format and may be reordered by mongod to increase performance.
What happens if an exception is thrown in MongoDB?
Since _id: 13 already exists, the following exception is thrown: Note that one document was inserted: The first document of _id: 13 will insert successfully, but the second insert will fail. This will also stop additional documents left in the queue from being inserted.
What is the default write concern in MongoDB?
An array of documents to insert into the collection. Optional. A document expressing the write concern. Omit to use the default write concern. Do not explicitly set the write concern for the operation if run in a transaction. To use write concern with transactions, see Transactions and Write Concern. Optional.