Implement datalink datatype, as specified by SQL/MED.
Implement additional operations on datalinks, such as reading and writing contents of files pointed to by datalinks.
This could be very useful for content management, workflow applications, etc... Right now this is rather clumsy, because some data is in a database and some is in files...
SQL/MED foreign data wrappers are planned, but not datalinks. At least I don't know of any plan.
This is planned. Please mark it so :)