oracle cursor  tutorial

I am studying oracle cursor

http://www.techonthenet.com/oracle/cursors/attributes.php

it has texts like below ......



Cursor with parameters
=======================

The basic syntax for a cursor with parameters is:

    CURSOR cursor_name (parameter_list)
    IS
        SELECT_statement;


For example, you could define a cursor called c2 as below.

    CURSOR c2 (subject_id_in IN varchar2)
    IS
        SELECT course_number
          from courses_tbl
          where subject_id = subject_id_in;

The result set of this cursor is all course_numbers whose subject_id matches the subject_id passed to the cursor via the parameter.

Cursor with return clause

The basic syntax for a cursor with a return clause is:

    CURSOR cursor_name
    RETURN field%ROWTYPE
    IS
        SELECT_statement;

For example, you could define a cursor called c3 as below.

    CURSOR c3
    RETURN courses_tbl%ROWTYPE
    IS
        SELECT *
          from courses_tbl
          where subject = 'Mathematics';

The result set of this cursor is all columns from the course_tbl where the subject is Mathematics.



My Queries:
===========
Q1.    see  CURSOR c2 (subject_id_in IN varchar2)

what is subject_id_in IN varchar2 ?

is it same as subject_id  varchar2  ??

is it saying that subject_id  has type varchar2 ??

i don't like "IN" keyword in the above .....can i remove that ?


Q2.
RETURN courses_tbl%ROWTYPE  .....what its doing ?

what is %ROWTYPE  ?

need some help here to understand this .

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