A concrete query holds in a concrete database, whose domain is nonempty, exactly when the query of the structure they give holds in its database; a packaged instance has a satisfied query exactly when the structure it encodes is a yes-instance of CQEval; the encoded structure has at most as many elements as the size of the instance; and the size of the instance is at most $2(e+1)^2$ for $e$ elements. The encoding neither pads nor compresses.