PL/SQL Error Return Multiple Rows - oracle

Question

I want to store some results in a temp table after I update a table but it is giving me an error for categories/book types that have multiple entries. Everything works fine when I try to do it with a book type that has one entry. Can someone tell me how I would fix this, I think it's got something to do with not having a filter although I'm not sure how I would do that.
DROP PROCEDURE UpdateAdvance;
CREATE OR REPLACE PROCEDURE UpdateAdvance (
p_BookType titles.category%TYPE,
p_NewAdvance advance_temptable.new_advance%TYPE) AS
CURSOR titles_cur IS
SELECT *
FROM titles
WHERE category=p_BookType
FOR UPDATE OF advance;
titles_rec titles_cur%ROWTYPE;
v_OldAdvance titles.advance%TYPE;
v_TitleID titles.title_id%TYPE;
v_Title titles.title%TYPE;
BEGIN
SELECT advance, title_id, title
INTO v_OldAdvance, v_TitleID, v_Title
FROM titles
WHERE category=p_BookType;
FOR titles_rec in titles_cur LOOP
INSERT INTO advance_temptable VALUES(advance_sequence.nextval, v_TitleID, v_Title, v_OldAdvance, p_NewAdvance);
END LOOP;
COMMIT;
END UpdateAdvance;
When I call it like this
BEGIN
UpdateAdvance('psychology', 100);
END;
I get the error:
Error starting at line : 35 in command -
BEGIN
UpdateAdvance('psychology', 100);
END;
Error report -
ORA-01422: exact fetch returns more than requested number of rows
ORA-06512: at "SYSTEM.UPDATEADVANCE", line 14
ORA-06512: at line 2
01422. 00000 - "exact fetch returns more than requested number of rows"
*Cause: The number specified in exact fetch is less than the rows returned.
*Action: Rewrite the query or change number of rows requested
Applied solution and here is what I now have working.
DROP PROCEDURE UpdateAdvance;
CREATE OR REPLACE PROCEDURE UpdateAdvance (
p_BookType titles.category%TYPE,
p_NewAdvance advance_temptable.new_advance%TYPE) AS
BEGIN
INSERT INTO advance_temptable
select advance_sequence.nextval, title_id, title, advance, p_NewAdvance
FROM titles
WHERE category=p_BookType;
COMMIT;
END UpdateAdvance;
BEGIN
UpdateAdvance('psychology', 100);
END;

Answer 1

Why don't you do:
INSERT INTO advance_temptable
select advance_sequence.nextval, TitleID, Title, Advance, p_NewAdvance
FROM titles
WHERE category = p_BookType;
without cursor?