As a result of running "chap04.sql" script downloaded from our course web site, it is supposed to create a database user named as "PRACTICE04" and several tables.

If you installed Oracle 12c in your computer, you may encounter the following error code:
"ORA-65094:invalid local user or role name" (If you unchecked "Create as Container Database" during Oracle installation, you will not face this problem. )

Becasue of the above error, it will not allow you to create a database user such as "PRACTICE04" in your database. Consequently, you will not be able to do the exercises as described in our class notes.

There are a few work-arounds for this problem. I recommend the following approach for our students in this class.

1. Use a text editor such as Notepad or Notepad ++, to open the file of "chap04.sql".
2. Find the following code in "chap04.sql" file:
   
   CONNECT system/&system_password;
   CLEAR SCREEN;
   
   
3. Below the line of "CLEAR SCREEN;" add the following code:
   
   alter session set "_oracle_script"=true;

You should be able to use "chap04.sql" and follow all the exercises as described in our class notes. Of course, if you do some research, you will be able to find other solutions to this problem. I encourage you to do your research and I sincerely welcome any other solutions. They are all acceptable as long as they work for you.