Fixed #29870 -- Added DurationField introspection for Oracle and PostgreSQL.

Thanks Tim Graham for the review.

django/db/backends/base/features.py

@@ -129,6 +129,9 @@ class BaseDatabaseFeatures:
     # Can the backend introspect an DecimalField, instead of an FloatField?
     can_introspect_decimal_field = True
 
+    # Can the backend introspect a DurationField, instead of a BigIntegerField?
+    can_introspect_duration_field = True
+
     # Can the backend introspect an IPAddressField, instead of an CharField?
     can_introspect_ip_address_field = False
 

django/db/backends/mysql/features.py

@@ -15,6 +15,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_date_lookup_using_string = False
     can_introspect_autofield = True
     can_introspect_binary_field = False
+    can_introspect_duration_field = False
     can_introspect_small_integer_field = True
     can_introspect_positive_integer_field = True
     introspected_boolean_field_type = 'IntegerField'

django/db/backends/oracle/introspection.py

@@ -18,6 +18,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         cx_Oracle.DATETIME: 'DateField',
         cx_Oracle.FIXED_CHAR: 'CharField',
         cx_Oracle.FIXED_NCHAR: 'CharField',
+        cx_Oracle.INTERVAL: 'DurationField',
         cx_Oracle.NATIVE_FLOAT: 'FloatField',
         cx_Oracle.NCHAR: 'CharField',
         cx_Oracle.NCLOB: 'TextField',

django/db/backends/postgresql/introspection.py

@@ -22,6 +22,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         1083: 'TimeField',
         1114: 'DateTimeField',
         1184: 'DateTimeField',
+        1186: 'DurationField',
         1266: 'TimeField',
         1700: 'DecimalField',
         2950: 'UUIDField',

django/db/backends/sqlite3/features.py

@@ -15,6 +15,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_mixed_date_datetime_comparisons = False
     autocommits_when_autocommit_is_off = True
     can_introspect_decimal_field = False
+    can_introspect_duration_field = False
     can_introspect_positive_integer_field = True
     can_introspect_small_integer_field = True
     supports_transactions = True