Removed unused foreign_key_re variables in MySQL/Oracle DB backends

import re

from collections import namedtuple

from MySQLdb.constants import FIELD_TYPE

FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('extra', 'default'))

InfoLine = namedtuple('InfoLine', 'col_name data_type max_len num_prec num_scale extra column_default')

foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")

class DatabaseIntrospection(BaseDatabaseIntrospection):

import re

import cx_Oracle

from django.db.backends.base.introspection import (

)

from django.utils.encoding import force_text

foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")

class DatabaseIntrospection(BaseDatabaseIntrospection):

    # Maps type objects to Django Field types.