xxxxxxxxxx
$rules['email'] = 'required|email|max:255|exists:DB_Name.user';
xxxxxxxxxx
/*
accepted: The field under validation must be yes, on, 1, or true.
active_url: The field under validation must be a valid URL according to PHP's checkdnsrr function.
after: The field under validation must be a value after a given date.
alpha: The field under validation must be entirely alphabetic characters.
alpha_dash: The field under validation may have alpha-numeric characters, as well as dashes and underscores.
alpha_num: The field under validation must be entirely alpha-numeric characters.
array: The field under validation must be a PHP array.
before: The field under validation must be a value preceding the given date.
between: The field under validation must have a size between the given min and max.
confirmed: The field under validation must have a matching field of foo_confirmation.
date: The field under validation must be a valid date.
date_format: The field under validation must match the given format.
different: The field under validation must have a different value than field.
digits: The field under validation must be numeric and must have an exact length of value.
digits_between: The field under validation must have a length between the given min and max.
email: The field under validation must be formatted as an e-mail address.
exists: The field under validation must exist on a given database table.
filled: The field under validation must not be empty when it is present.
image: The file under validation must be an image (jpeg, png, bmp, gif, svg, or webp).
in: The field under validation must be included in the given list of values.
/*