dbchild   INTEGER            REFERENCES revision,

	    -- The main payload of the revision are the date/time it
	    -- was entered, its state, operation (= type/class), text
	    -- content, and meta data (author, log message, branch,
	    -- project). The last is encoded as single id, see table
	    -- 'meta'. The date/time is given in seconds since the
	    -- epoch, for easy comparison. The text content is an
	    -- epoch, for easy comparison.
	    -- (offset,length) pair into the rcs archive.

	    op    INTEGER  NOT NULL  REFERENCES optype,
	    date  INTEGER  NOT NULL,
	    state TEXT     NOT NULL,
	    mid   INTEGER  NOT NULL  REFERENCES meta,
	    coff  INTEGER  NOT NULL,
	    clen  INTEGER  NOT NULL,

	    UNIQUE (fid, rev) -- The DTN is unique within the revision's file.
	}

	# Blobs contain the information needed to extract revisions
	# from rcs archive files. As such each revision has an
	# associated blob. However we can have blobs without