Kimberly Israel, 17.09.2013 14:33:
> Yesterday I created several tables and was able to run queries that
> combined data from more than one table at a time, but when I reopened
> pgAdmin III today, the database I had created was there, but the
> tables were all gone. I tried to save my work, but what got saved
> was a .sql file that seems to only contain the code for creating the
> database. Basically what I need to know is how do I put my tables
> somewhere where I'll be able to continue working with them after a
> period of having the computer off?
This all sounds like you forgot to commit your changes.
When you have auto-commit disabled you need to commit every change you make to the database - including a CREATE TABLE statement.