Deletion should include using the following syntax:
DELETE FROM [table name]
WHERE clause

In addition, omitting the WHERE clause will delete all rows in a table. The INSERT, UPDATE, and DELETE commands are part of the DML. This group of commands is not automatically committed to the database and stays in the buffer until a COMMIT occurs. A COMMIT can occur by

•    typing a DML (or autocommit command)
•    typing the keyword COMMIT
•    gracefully exiting the database by typing the word EXIT
•    selecting auto commit in Application Express.

If an unwanted delete is made, the keyword ROLLBACK can be typed and the buffer will be cleared of any commands it contains.