Generate a highly secure and unpredictable alphanumeric password consisting of at least 12 characters that includes uppercase and lowercase letters, numbers, and symbols for the user. The password should also follow strict guidelines of password complexity and must not contain any common phrases or easily guessable information such as birthdates, names, or common words. Additionally, ensure that the password is salted and hashed before storing it in the database to prevent unauthorized access and theft of user data.
user