在一个猫鼬命令中更新多个文档

Question

I have the following collection

[ { a : 'One', b : 'Two' }, { a : 'Three', b : 'Four' } ]

I want to update the collection in single query such that i will append substring 'numbered' to each of the 'a' property of each document in collection.

resultant collection should be :

[ { a : 'Onenumberd', b : 'Two' }, { a : 'Threenumbered', b : 'Four' } ]

How can i achieve the same in single mongoose query?

Answer 1

It is not currently possible to reference the existing value of any field when performing an update(). You could find open JIRA ticket https://jira.mongodb.org/browse/SERVER-1765

So only way for now is to query and then update using retrieved data.

Answer 2

You should use the $concat operator from the aggregation framework. The code should be quite similar in mongoose as well.