Longest practical filter for an alert

Question

Environment: SP2010 Enterprise SP1, Server/SQL 2008 R2, VS2012

When building alerts through object model, what is the longest or most complex CAML filter that can be applied to them? Can they be as complex as I want, or is there a set number or other practical limit (like performance impact) that restricts them?

For example, this is a valid filter that specifies a certain folder and all its sub-folders:

@"<Query>" +
    @"<Or>" +
        @"<Eq>" +
            @"<FieldRef Name='ItemFullUrl'/>" +
            @"<Value Type='string'>" + fullPath + @"</Value>" + //Everything in the folder
        @"</Eq>" +
        @"<BeginsWith>" +
            @"<FieldRef Name='ItemFullUrl'/>" +
            @"<Value Type='string'>" + fullPath + @"/</Value>" + //Everything in sub-folders
        @"</BeginsWith>" +
    @"</Or>" +
@"</Query>";

But what if I strung a dozen of those together with <Or> statements to make it cover multiple directories?

Edit: Bonus question, how deep can you nest something in the filter? The GUI never lets you go down more than one level (<And><Or></Or></And>) but is it possible to do more?

Thanks for any help you can provide!

Answer 1

It seems unlikely that they did not reuse the Query parser from the list/view/query in the web services. IF that is the case you could experiment your way into the answer using this tool: http://www.codeproject.com/Articles/458008/CAML-Query-Builder

Point it at the list you want to target and make the most complex query you need and see how it works. Once again, I suppose I am just providing the way I would find an answer to your question, not really answering it.

Jon