Are you referring to 2003 or 2007? The database structures are different.
In 2003 they are stored in MSP_LINKS.
The schema of the 2003 database is installed on the Project Server front end
automatically. Here is an excerpt from that schema file about link: "Task
links, or dependencies, are stored in the MSP_LINKS table. Each row defines
an association between a predecessor and successor task. Each row defines
only one such association. Multiple links to a given task require a row for
each link."
Hope this helps,
Jonathan Sofer