Since you're using PostgreSQL, you can ask it directly if a table exists, with something like this:

SELECT relhasindex, relkind, relchecks, reltriggers, relhasrules
FROM pg_class WHERE relname='day_20030218';
[download]

I also have to suggest that separate tables for each day is a poor use of the power of a database unless you are running into per-table capacity issues (unlikely with PostgreSQL.) There's a good set of pages from the University of Texas about database design that I point people to all the time.

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Spring: Forces, Coiled Again!