Explanation:
CREATE USER and CREATE TABLE do not produce an entry in the alert log file.The alert logstores information that is extremely useful in order to know the health of the database. It records the starting and stopping of the databases, creation of new redo log file (which happens every time a log switch occurs), creation of tablespaces, addition of new datafiles to the tablespaces, and most importantly the errors that are generated by Oracle.
Reference:
OCP Oracle 9i Database: Fundamentals I, p. 64.

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