Question

I have some collection and I want to perform action on every insert into that collection. The problem is that the code, that will do this actions is in Java. In Oracle it was possible to wrap Java or even C code into PL/SQL procedure, and then use this procedure in trigger. In CouchDB we could write a view. What would be the closest analog for MongoDB?
The best possibility I can think of is to wrap my code into REST server, and then interact with it using stored javascript.

I’ve already seen this question, but due to dependency on java libs, I can’t use just javascript in my workflow, neither I don’t want to run a new heavy service along with mongodb if there is some other way to do this.

Answer 1

There are a number of things to say about your request:

I have some collection and I want to perform action on every insert into that collection.

1) What you’re asking for here is not really a “stored procedure”, but really is a “database trigger”. MongoDB does not provide any sort of “database trigger” functionality.

This is consistent with the general design goals of MongoDB, which is to provide a very fast, scalable data store without the heavy weight of traditional DBMS systems. See this presentation for more details about the design goals of MongoDB: http://www.10gen.com/presentations/mongosf2011/whymongodb

2) If there is some data processing that you’d like to perform on every insert, you’ll need to do it on the client side of the MongoDB connection. This will necessarily involve writing some code in your application.

3) I’d suggest that you avoid running JavaScript within the mongod server if at all possible. The JavaScript is interpreted on the server side, so the speed of your queries will be affected. In addition, all JavaScript run in the mongod server is single-threaded, so there is no concurrency of any JavaScript execution.

I wish I had a better answer for you.