Meteor/Mongo: Finding and updating certain elements in a collection

Question

I'm starting off with Meteor and need some help with Mongo. I have a collection of names that I'm displaying on a list and want to be able to update one variable of certain entries in the database based on other criteria. Basically what I want to do is: For every entry where characteristic A = true and B = true, change characteristic C to be false. So far, I've been trying to figure out how Mongo can handle a "for each" loop over the elements of the collection, and for each element check if conditions A and B hold, and then collection.update(element, {C: false}). This is proving to be a lot more problematic than I thought. I want to do something like this (using dummy variable names): ``` for (i = 0; i < collection.find().count(); i++){ if (collection[i].A===true && collection[i].B===true) collection.update(collection[i], {$set: {C: false}}); }; ``` I've been changing this base code around, but am starting to sense that I'm missing something basic about indexing/how collections work i…

Accepted Answer

Of course I figure out how to do this right after posting, and of course it's suggested in the Meteor documentation!

And, of course, it's a simple solution:

```
collection.update({A: true, B: true}, {$set: {C:false}});
```

Meteor/Mongo: Finding and updating certain elements in a collection

Solution

Problem