I've just put together a sample database abstraction layer to a MySQL database, for demonstration purposes:
The idea (not all these features are working yet) is to allow read only access via the above methodology. _ENTIRE_CONTENTS will return a CSV representation of the data (assuming no large objects or equivalent). If the table has a SINGLE primary key, records will be listed as resources with names as those keys - these have no content but all attribute fields are available as live properties of these resources.
Trying to implement these highlighted some weaknesses in the server - it is too file oriented. Properties like modified/creation date may not mean anything to a record or table, and contentlength is a problem - there is no file size, so the only way to calculate the content length for a table.... is to retrieve ALL the content.
The solution here is to tweak the server to make these optional, such that if contentlength or modified date support is not provided, server will not use them (no last modified, no IF_(UN)MODIFIED_SINCE matching for example) or return the corresponding headers, and to support some other properties that were previously left out since they did not have too much to do with files, like getcontentlanguage.
Not all of this will appear by the SoC deadline, but most likely by mid-September (next release).