Account Management Statements DBAs can enforce non-reuse by establishing an appropriate password-reuse policy. See Password Reuse Policy. ALTER USER  permits these  password_option  values for controlling password expiration: Immediately marks the password expired for all accounts named by the statement. Sets all accounts named by the statement so that the global expiration policy applies, as specified by the default_password_lifetime  system variable. This expiration option overrides the global policy for all accounts named by the statement. For each, it disables password expiration so that the password never expires. This expiration option overrides the global policy for all accounts named by the statement. For each, it sets the password lifetime to  N  days. The following statement requires the password to be changed every 180 days: ALTER USER  permits these  password_option  values for controlling reuse of previous passwords based on required minimum number of password changes: Sets all accounts named by the statement so that the global policy about password history length applies, to prohibit reuse of passwords before the number of changes specified by the password_history  system variable. This history-length option overrides the global policy for all accounts named by the statement. For each, it sets the password history length to  N  passwords, to prohibit reusing any of the  N  most recently chosen passwords. The following statement prohibits reuse of any of the previous 6 passwords: ALTER USER  permits these  password_option  values for controlling reuse of previous passwords based on time elapsed: Sets all statements named by the account so that the global policy about time elapsed applies, to prohibit reuse of passwords newer than the number of days specified by the password_reuse_interval  system variable. 2847 • PASSWORD REUSE INTERVAL DEFAULT • PASSWORD HISTORY  N • PASSWORD HISTORY DEFAULT • PASSWORD EXPIRE INTERVAL  N  DAY • PASSWORD EXPIRE NEVER • PASSWORD EXPIRE DEFAULT • PASSWORD EXPIRE ALTER USER ’jeffrey’@’localhost’ PASSWORD EXPIRE; ALTER USER ’jeffrey’@’localhost’ PASSWORD EXPIRE DEFAULT; ALTER USER ’jeffrey’@’localhost’ PASSWORD EXPIRE NEVER; ALTER USER ’jeffrey’@’localhost’ PASSWORD EXPIRE INTERVAL 180 DAY; ALTER USER ’jeffrey’@’localhost’ PASSWORD HISTORY DEFAULT; ALTER USER ’jeffrey’@’localhost’ PASSWORD HISTORY 6;