2011/10/11 Robert Haas <robertmh...@gmail.com>: > On Tue, Oct 11, 2011 at 4:40 AM, Pavel Stehule <pavel.steh...@gmail.com> > wrote: >> Hello >> >> A current limits of dynamic work with row types in PL/pgSQL can be >> decreased with a possible casts between rows and arrays. Now we have a >> lot of tools for arrays, and these tools should be used for rows too. >> >> postgres=# \d mypoint >> Composite type "public.mypoint" >> Column │ Type │ Modifiers >> ────────┼─────────┼─────────── >> a │ integer │ >> b │ integer │ >> >> postgres=# select cast(rmypoint '(10,20) as int[]); >> array >> ──────────── >> {10,20} >> (1 row) >> >> postgres=# select cast(ARRAY[10,20] AS mypoint); >> mypoint >> ───────── >> (10,20) >> (1 row) >> >> What do you think about this idea? > > Well, a ROW can contain values of different types; an ARRAY can't.
yes, I know - but it should be problem only in few cases - when is not possible to cast a row field to array field. This is based on user knowledge - it has to choose a adequate array type sometimes he can use a numeric or int array, sometimes he have to select text array. Target type is selected by user, and cast fail when conversion is not possible. Pavel > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers