I think Matthew nailed it.
Actually, now that I think of it I think the conceptual difficulty is in the misuse of tabs here. You have a table of contents (with some details about each entry) and links to individual items. So this is in fact a hierarchy but the UI presents it as two structures that are on the same level.
So I completely agree that the single views should be available, but I do not think it should have a tab of its own, since it is the tab I can not think of a usage scenario for it. A simple return link to the listing with next/prev navigation would probably work - not unlike most blogs, actually.
In fact, now that I look at the tabs I do not think the database app has any reason to have any tabs, since none of the tabs comply to the metaphor of tabs. Add entry is a command, so it should simply have a command button with a separate page with a simple return link to the database, or maybe even a YUI dialog. Search should probably be a simple text field right on every page of the database (plus just a link to an advanced search form), like on most websites (this is a strong convention users are used to http://www.useit.com/alertbox/20040913.html and I believe this probably is not obsolete).
I would like to take a further look at this and compare similar applications. Then a blasamiq mockup + iterative usability testing. No major change in functionality, I guess - perhaps maybe a new look at the HTML templating mentioned above?
Not sure what is planned for this though, since Navigation 2.0 seems to mean tabs are going away anyway.