You want to add a column to table foo.
Either:
1. Create a new table bar with the additional field, copy the data over then delete foo and rename bar
2. Use the ALTER TABLE ADD COLUMN command
The first has the advantage that you can make more radical changes than just adding a column. The second is much quicker ref.
Even the best design needs occasional tweaking. To add a city column to the companies table you would use
ALTER TABLE companies ADD COLUMN city(text); |
You can also add indices and constraints to a table, rename columns or change the owner of a table. If you find something you can't do just follow solution 1.