You might be able to get the subject from the ost_ticket__cdata table, but thats not the authority. any __Cdata table is a temporary table and the information is being pulled from where where and stored there to speed up the system.

The data is actually stored in the ost_form_entry_values table.

You can find it by doing something like:
SELECT id FROM ost_form_entry WHERE object_id=##### LIMIT 1;
Where ##### is the ticket_id (mouse over the ticket in ui to see its ID or look at the ost_ticket table.

Then use the id to look up field_id 5
SELECT value FROM ost_form_entry_values WHERE entry_id=$id and field_id=5;

This should return the subject / issue summary.

Thanks @ntozier, I had thought the cdata tables were temporary but wasn't sure where else to look. I'll file this away for future reference