Well, it's not so much that there is a specific relationship between the primary key and the value, in this case the primary key is just a serial value.
So, for example if the columns are:
id, item_name (varchar) amount_in_stock (integer), and I want to add an integer column (minimum_required_amount) using alter table, how do i then load values for this column into the table? There isn't a relationship per se between the key and the new column. I tried doing an update my_table set minimum_required_amount = (10, 20,30,20,10);
but postgres doesn't seem to like this. Basically, I just want to load this data in starting at the first row into the minimum_required_amount column.