Introduction to rowid and rownum in Oracle

Q: Does Oracle differentiate ROWID from ROWNUM? If they have differences, what are their differences?

A: Just as your address uniquely identifies your location, an oracle rowid uniquely identifies the physical address of a piece of data.
Rowid provides all the information you need to find this row of data, hard disk number, cylinder, block and the offset address on the block.
Rownum is a pseudo code, a placeholder that you can reference in SQL * Plus. Rownum can be used to write professional SQL statements and adjust SQL statements.

Note the following when using rownum in SQL statements:
Correct: where rownum <n;
Where rownum = 1;
Error: where rownum> n;
Where rownum = some_num> 1
This is correct if you have:
Select * from (
Select rownum rn, t. * from t
)
Where rn = 3;

For example, to display the first five pieces of data, you can use rownum as a filter:
SQL> select rownum, emp. empno, emp. ename, emp. job from emp
2 where rownum <= 5;

ROWNUM EMPNO ENAME JOB
----------------------------------
1 7369 SMITH CLERK
2 7499 ALLEN SALESMAN
3 7521 WARD SALESMAN
4 7566 JONES MANAGER
5 7654 MARTIN SALESMAN

In short, the difference between rowid and rownum is that rownum is temporary while rowid is permanent.
In addition, rowid can be used to obtain a data row. rowid is meaningful only in the content of a single SQL statement. It is a way to retrieve a dataset by reference.

SQL> select rownum, rowid, empno, initcap (ename), initcap (job), sal from emp;

Rownum rowid empno initcap (ENAME) INITCAP (JOB) SAL
--------------------------------------------------------------------
1 AAAL + ZAAEAAAAAdAAA 7369 Smith Clerk 800.00
2 AAAL + ZAAEAAAAAdAAB 7499 Allen Salesman 1600.00
3 AAAL + ZAAEAAAAAdAAC 7521 Ward Salesman 1250.00
4 AAAL + ZAAEAAAAAdAAD 7566 Jones Manager 2975.00
5 AAAL + ZAAEAAAAAdAAE 7654 Martin Salesman 1250.00
6 AAAL + ZAAEAAAAAdAAF 7698 Blake Manager 2850.00
7 AAAL + ZAAEAAAAAdAAG 7782 Clark Manager 2450.00
8 AAAL + ZAAEAAAAAdAAH 7788 Scott Analyst 3000.00
9 AAAL + ZAAEAAAAAdAAI 7839 King President 5000.00
10 AAAL + ZAAEAAAAAdAAJ 7844 Turner Salesman 1500.00
11 AAAL + ZAAEAAAAAdAAK 7876 Adams Clerk 1100.00
12 AAAL + ZAAEAAAAAdAAL 7900 James Clerk 950.00
13 AAAL + ZAAEAAAAAdAAM 7902 Ford Analyst 3000.00
14 AAAL + ZAAEAAAAAdAAN 7934 Miller Clerk 1300.00