function is_valid_email

function is_valid_email(
    p_value in varchar2
) return boolean

returns true if value is valid email address

function is_valid_email2

function is_valid_email2(
    p_value in varchar2
) return boolean

returns true if value is valid email address

function is_valid_email_list

function is_valid_email_list(
    p_value in varchar2
) return boolean

returns true if value is valid email address list