From: Mario Domenech Goulart <address@hidden>
Subject: [Chicken-users] Doubts about the postgresql egg
I'm trying to use the postgres egg and I have some doubts about how to
use it.
A basic (maybe silly) question: if I just want to perform an
`insert', `create table' or something that doesn't return data
from tables, do I have to use something like:
(pg:query-for-each
(lambda (_) _)
"insert something into my-table" conn)
or is there a better way to do that?
Now a problem I'm having with pg:query-tuples (chicken 2.41). I have a
simple database:
$ psql test
Welcome to psql 8.0.4, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit
test=> \d test
Table "public.test"
Column | Type | Modifiers
--------+------+-----------
v1 | text |
v2 | text |
test=> select * from test;
v1 | v2
----+----
a | b
(1 row)
If I try the following code:
,----[ test.scm ]
| #!/usr/bin/csi -script
|
| (use postgresql)
|
| (let ((db (pg:connect '((dbname . "test")))))
| (pg:query-tuples "select * from test" db)
| (pg:close db))
`----
I get:
$ ./test.scm
Error: Wrong seed count
(expected 1)
(got 0)
Call history:
<eval> (##sys#require (quote postgresql))
<eval> (pg:connect (quote ((dbname . "test"))))
<eval> (pg:query-tuples "select * from test" db) <--
I get the expected result when I use pg:query-for-each:
,----[ test2.scm ]
| #!/usr/bin/csi -script
|
| (use postgresql)
|
| (let ((db (pg:connect '((dbname . "test")))))
| (pg:query-for-each
| (lambda (tuple)
| (pp tuple))
| "select * from test" db)
| (pg:close db))
`----
$ ./test2.scm
#("a" "b")
Is there something I'm missing about pg:query-tuples?
Best wishes,
Mario