How to find by partial binary over BinData field in mongodb?

Question

I have a BinData field in my mongo and I need to make a find over it with partial information.

Let's say that the bindata that I have looks like this:

{ "_id" : ObjectId("5480356518e91efd34e9b5f9"), "test" : BinData(0,"dGVzdA==") }

If I do this query I get the result:

> db.test.find({"test" : BinData(0,"dGVzdA==")})
{ "_id" : ObjectId("5480356518e91efd34e9b5f9"), "test" : BinData(0,"dGVzdA==") }

However I would like to find it with only a part of the binary object.
Is it possible?

Thanks!

Answer 1

"partial" is a vague term - if you're searching for a contiguous block of binary data (needle) at any point in the haystack, you're going to need a very different solution I think, maybe something based on a suffix tree / suffix array for binary data.

If you want to find binary data that starts with specific bytes, you might want to consider storing the data as hex or base64 encoded strings and use a rooted regex for index use. But that is fraught with its own perils (padding, endianness, etc.) and incredibly ugly...

Isn't there a way to store the binary data in a way that MongoDB understands it? That might be easier...