Sam Mason wrote: > > But for rows, there is no such thing. You can't assign null to a row, it > > makes no sense and actually causes an error. > > What makes you say this? There's no reason I can see that would cause > row values should be special in this way. Maybe if you could define > what you mean by "you can't assign null to a row"? It seems to me that there is something special with rows: in tables, the values of columns may be null or not, but at the level of the row, there is no information that would say: this row itself as an object is null. Anyway, let's try to assign null to a row variable (with 8.4.0): CREATE TABLE our_table(i int); CREATE FUNCTION test() returns void as $$ declare r our_table; begin r:=null; end; $$ LANGUAGE plpgsql; SELECT test() yields: ERROR: cannot assign non-composite value to a row variable CONTEXT: PL/pgSQL function "test" line 4 at assignment As a follow-up to the comparison between rows and arrays, note that if we'd make r an int[], there would be no error. However, I agree that if we consider that a row is a composite type, then there is a problem because we sure can insert NULL into a column that is of a composite type. So the "row cannot be null" line of reasoning holds only so far as you don't stuff rows into columns :) Best regards, -- Daniel PostgreSQL-powered mail user agent and storage: http://www.manitou-mail.org -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
