Get a list of column names from a psycopg2 cursor executing stored proc?

Question

I'm trying to get a list of column names after calling my postgres stored proc via psycopg2 in python...

Here's my code

# create a connection to the database
conn = psycopg2.connect(...)

# create a cursor object for execution
curs = conn.cursor()
curs.callproc('usp_my_stored_proc', ['mySP'])

# now open a new cursor & "steal" the recordset from the previous cursor
curs2 = conn.cursor('mySP')

# close cursor & connection
curs2.close()
curs.close()
conn.close()

Now I want to print out the columns of my stored proc and make them headers for my CSV file - I've search and I haven't found any leads...

Advice / Help is definitely welcome...

piro · Accepted Answer · 2018-03-01 16:41:44Z

Two ways

1) after fetching one record, curs2.description will contain names and types:

>>> curs.execute("declare cu cursor for select a, a*2 as b from generate_series(1,10) x(a);") 
>>> curs2 = cnn.cursor('cu')

>>> curs2.description

>>> curs2.fetchone()
(1, 2)

>>> curs2.description
(Column(name='a', type_code=23, display_size=None, internal_size=4, precision=None, scale=None, null_ok=None),
 Column(name='b', type_code=23, display_size=None, internal_size=4, precision=None, scale=None, null_ok=None))

2) inspect the postgres system catalog:

=# create function my_thing(p1 int, p2 int, out o1 int, out o2 int) returns setof record language sql as $$select a, a*2 from generate_series(p1,p2) x(a)$$;
CREATE FUNCTION

=# select * from my_thing(3,5);
 o1 | o2 
----+----
  3 |  6
  4 |  8
  5 | 10

=# select proargmodes, proargnames, proallargtypes from pg_proc where proname = 'my_thing';
 proargmodes |  proargnames  | proallargtypes 
-------------+---------------+----------------
 {i,i,o,o}   | {p1,p2,o1,o2} | {23,23,23,23}

See pg_proc docs for the meaning of the fields.

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