Question

PostgreSQL does not allow altering a view (i.e. adding column, changing column orders, adding criterie etc.) if it has dependent objects. This is really getting annoying since you have to write a script to:

1. Drop all the dependent objects,
2. Alter the view,
3. Recreate all the dependent objects back again.

I understand that postgreSQL developers have very reasonable concerns to prevent altering views. But do you guys have any scripts/shot-cuts to do all those manual stuff in a single run?

Answer 1

Adding new columns isn’t a problem, changing datatypes or changing the order of the columns, that’s where you get problems.

1. Don’t change the order, it’s not
   that important anyway, just change your query:

   SELECT a, b FROM view_name;

   SELECT b, a FROM view_name;

2. When you have to change a datatype
   of a column, you have to check the
   depend objects as well. These might
   have problems with this new
   datatype. Just get the definition of
   this object and recreate after the
   changes. The information_schema and
   pg_catalog help you out.

3. Make all changes within a single
   transaction.