Fixed #27859 -- Ignored db_index for TextField/BinaryField on Oracle and MySQL.

Thanks Zubair Alam for the initial patch and Tim Graham for the review.

1 files changed, 22 insertions, 0 deletions

diff --git a/django/db/backends/oracle/validation.py b/django/db/backends/oracle/validation.py
new file mode 100644
index 0000000000..e5a35fd3ca
--- /dev/null
+++ b/django/db/backends/oracle/validation.py
@@ -0,0 +1,22 @@
+from django.core import checks
+from django.db.backends.base.validation import BaseDatabaseValidation
+
+
+class DatabaseValidation(BaseDatabaseValidation):
+    def check_field_type(self, field, field_type):
+        """Oracle doesn't support a database index on some data types."""
+        errors = []
+        if field.db_index and field_type.lower() in self.connection._limited_data_types:
+            errors.append(
+                checks.Warning(
+                    'Oracle does not support a database index on %s columns.'
+                    % field_type,
+                    hint=(
+                        "An index won't be created. Silence this warning if "
+                        "you don't care about it."
+                    ),
+                    obj=field,
+                    id='fields.W162',
+                )
+            )
+        return errors