I need to insert a new document if it doesn't exist yet, or return an existing document if it already exists.
db.projects.findAndModify({
query: {parentProjectId: "project:522755ba0d8686aa6f356393", name: "Eisner" },
update: { $setOnInsert: {_id: "project:79792889929982797297972797222"} },
upsert: true
})
However Mongo fails with an error:
"errmsg" : "exception: Mod on _id not allowed", "code" : 10148, "ok" : 0
I can see why this would be a problem with a $set but not why it would have to fail with a $setOnInsert. The document that is about to be inserted hasn't been inserted yet.
- duplicates
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SERVER-9958 $setOnInsert should allow _id to be set
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- Closed
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- is related to
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- Closed
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