Migrations - cannot add a new materialized field after a regular field

CHANGELOG.md

@@ -6,6 +6,7 @@ Unreleased
 - Added `timeout` parameter to database initializer (SUHAR1K)
 - Added `verify_ssl_cert` parameter to database initializer
 - Added `final()` method to querysets (M1hacka)
+- Fixed a migrations problem - cannot add a new materialized field after a regular field
 
 v1.0.3
 ------

src/infi/clickhouse_orm/migrations.py

@@ -75,13 +75,16 @@ class AlterTable(Operation):
         # Identify fields that were added to the model
         prev_name = None
         for name, field in iteritems(self.model_class.fields()):
+            is_regular_field = not (field.materialized or field.alias)
             if name not in table_fields:
                 logger.info('        Add column %s', name)
                 assert prev_name, 'Cannot add a column to the beginning of the table'
-                cmd = 'ADD COLUMN %s %s AFTER %s' % (name, field.get_sql(), prev_name)
+                cmd = 'ADD COLUMN %s %s' % (name, field.get_sql())
+                if is_regular_field:
+                    cmd += ' AFTER %s' % prev_name
                 self._alter_table(database, cmd)
 
-            if not field.materialized and not field.alias:
+            if is_regular_field:
                 # ALIAS and MATERIALIZED fields are not stored in the database, and raise DatabaseError
                 # (no AFTER column). So we will skip them
                 prev_name = name

tests/test_migrations.py

@@ -93,10 +93,10 @@ class MigrationsTestCase(unittest.TestCase):
         self.database.migrate('tests.sample_migrations', 14)
         self.assertTrue(self.tableExists(MaterializedModel1))
         self.assertEqual(self.getTableFields(MaterializedModel1),
-                          [('date_time', "DateTime"), ('int_field', 'Int8'), ('date', 'Date')])
+                          [('date_time', 'DateTime'), ('int_field', 'Int8'), ('date', 'Date'), ('int_field_plus_one', 'Int8')])
         self.assertTrue(self.tableExists(AliasModel1))
         self.assertEqual(self.getTableFields(AliasModel1),
-                          [('date', 'Date'), ('int_field', 'Int8'), ('date_alias', "Date")])
+                          [('date', 'Date'), ('int_field', 'Int8'), ('date_alias', 'Date'), ('int_field_plus_one', 'Int8')])
 
 
 # Several different models with the same table name, to simulate a table that changes over time
@@ -183,6 +183,7 @@ class MaterializedModel1(Model):
     date_time = DateTimeField()
     date = DateField(materialized='toDate(date_time)')
     int_field = Int8Field()
+    int_field_plus_one = Int8Field(materialized='int_field + 1')
 
     engine = MergeTree('date', ('date',))
 
@@ -206,6 +207,7 @@ class AliasModel1(Model):
     date = DateField()
     date_alias = DateField(alias='date')
     int_field = Int8Field()
+    int_field_plus_one = Int8Field(alias='int_field + 1')
 
     engine = MergeTree('date', ('date',))