If I am not mistaken, this accurately describes the limits of MongoDB in terms of mapping relations. I'm not a Mongo expert because no one could convince me otherwise to date, somebody correct me?
>You are referring to using an index, correct? Because grep is absolutely, madly efficient for a doing a full search.
I'm not sure why you imply that a full search is incompatible with an index.
Perhaps you meant "full scan", that is reading everything while searching, instead of "full search" (searching everything). The first is not a prerequisite for the second.
In any case, grep is a very inefficient way of doing a full search. An index is so much faster it's not even funny.
>The index portion of a file system are called files and directories.
Those are just indexes for the names of the files and folders, and a few other select metadata. Nothing like a full-text search index, or even actual indexes on metadata.
(Some filesystems allow those too, e.g. in BeOS, but nowhere as comprehensive and flexible as using a dedicated tool for this, be it MongoDB or something else).
>Several file names can refer to the same data. Those are called hard links. So with hard links, I can refer to a Foo by their related Bar.
Sounds like a convoluted and inefficient way of building something somewhat like a "document database" with 1/10 the features (if that).
>I'm not a Mongo expert because no one could convince me otherwise to date, somebody correct me?
I'm far from a fan of Mongo, but you seem like you have already made up your mind, and nothing will change it.
Plus, if a filesystem is enough of a document database for you (with no cheating, e.g piling up tons of hacks and add-ons like external full-text scanning tools), then be all means, us one.