Fixed #30593 -- Added support for check constraints on MariaDB 10.2+.

1 files changed, 6 insertions, 0 deletions

diff --git a/django/db/backends/mysql/schema.py b/django/db/backends/mysql/schema.py
index 666aa292e8..9b80b9bede 100644
--- a/django/db/backends/mysql/schema.py
+++ b/django/db/backends/mysql/schema.py
@@ -28,9 +28,15 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
     sql_delete_pk = "ALTER TABLE %(table)s DROP PRIMARY KEY"
 
     sql_create_index = 'CREATE INDEX %(name)s ON %(table)s (%(columns)s)%(extra)s'
+    # The name of the column check constraint is the same as the field name on
+    # MariaDB. Adding IF EXISTS clause prevents migrations crash. Constraint is
+    # removed during a "MODIFY" column statement.
+    sql_delete_check = 'ALTER TABLE %(table)s DROP CONSTRAINT IF EXISTS %(name)s'
 
     def quote_value(self, value):
         self.connection.ensure_connection()
+        if isinstance(value, str):
+            value = value.replace('%', '%%')
         # MySQLdb escapes to string, PyMySQL to bytes.
         quoted = self.connection.connection.escape(value, self.connection.connection.encoders)
         if isinstance(value, str) and isinstance(quoted, bytes):