Question 6 :
The semicolon terminates a SQL statement (and executes it).
Question 7 :
SQL*Plus is a text editor.
Question 8 :
When you type Start FILENAME, the statement in your file will be executed automatically.
Question 9 :
You can check on the status of tables with the DESCRIBE or DESC command.
Question 10 :
Oracle directly supports the definition of surrogate keys.