diff --git a/django/core/db/backends/mysql.py b/django/core/db/backends/mysql.py
index c51b357becf..3c0924e53f2 100644
--- a/django/core/db/backends/mysql.py
+++ b/django/core/db/backends/mysql.py
@@ -95,6 +95,7 @@ DATA_TYPES = {
     'IPAddressField':    'char(15)',
     'ManyToManyField':   None,
     'NullBooleanField':  'bool',
+    'OneToOneField':     'integer',
     'PhoneNumberField':  'varchar(20)',
     'PositiveIntegerField': 'integer UNSIGNED',
     'PositiveSmallIntegerField': 'smallint UNSIGNED',
diff --git a/django/core/db/backends/postgresql.py b/django/core/db/backends/postgresql.py
index 8de25f0d574..ded611376de 100644
--- a/django/core/db/backends/postgresql.py
+++ b/django/core/db/backends/postgresql.py
@@ -105,6 +105,7 @@ DATA_TYPES = {
     'IPAddressField':    'inet',
     'ManyToManyField':   None,
     'NullBooleanField':  'boolean',
+    'OneToOneField':     'integer',
     'PhoneNumberField':  'varchar(20)',
     'PositiveIntegerField': 'integer CHECK (%(name)s >= 0)',
     'PositiveSmallIntegerField': 'smallint CHECK (%(name)s >= 0)',