basic stored procedure (update column value) - stored-procedures

Question

I have a basic table that looks like the following:
SQL> desc comments
Name Null? Type
---------------------------------------
COMMENT_ID NOT NULL NUMBER
POST_ID NOT NULL NUMBER
USER_ID NOT NULL NUMBER
MESSAGE NOT NULL VARCHAR2(2500)
MESSAGE_TIME NOT NULL TIMESTAMP(6)
UPVOTES NOT NULL NUMBER
What I'd like to do is have a stored procedure be called that would increment the upvotes. This seems to make the most sense because I don't want to pass in anything other than the comment_id and post_id.
I think I should be doing something like this (please excuse syntax, I haven't messed with stored procedures in a long long time)
CREATE OR REPLACE procedure proc_upvote_comment (comment_id NUMBER , post_id NUMBER)
BEGIN
SELECT UPVOTES FROM COMMENTS
WHERE COMMENTS.COMMENT_ID = proc_upvote_comment.comment_id
AND COMMENTS.POST_ID = proc_upvote_comment.post_id;
//Call an update
END;
/
But I just don't seem to know the missing piece here. I've tried looking at
http://docs.oracle.com/cd/B19306_01/appdev.102/b14251/adfns_packages.htm#i1007682
http://docs.oracle.com/cd/B12037_01/server.101/b10759/statements_6009.htm
And a few other places on the site - but I'm just missing something.
Any help in the right direction would be great

Answer 1

Is there any reason this is not working for you:
CREATE OR REPLACE procedure proc_upvote_comment (comment_id NUMBER , post_id NUMBER)
AS
BEGIN
UPDATE COMMENTS
SET UPVOTES = UPVOTES + 1
WHERE COMMENTS.COMMENT_ID = proc_upvote_comment.comment_id
AND COMMENTS.POST_ID = proc_upvote_comment.post_id;
END;
Remember that SQL works with sets ;)

Answer 2

You probably just want
CREATE OR REPLACE procedure proc_upvote_comment (p_comment_id NUMBER , p_post_id NUMBER)
AS
BEGIN
UPDATE comments
SET upvotes = upvotes + 1
WHERE comment_id = p_comment_id
AND post_id = p_post_id;
END;
/
Generally, you want to have a naming convention to differentiate parameters from column names. I prefer using the p_ prefix for parameters and the l_ prefix for local variables but there are other conventions. If you don't do this and you use the same name for a column and for a parameter, the SQL statement will resolve identifiers first using the name of the column and then using the name of the parameter. Resorting to prefixing the name of the stored procedure to provide scope resolution works but it's rather cumbersome.