[migration] add server side constraint for Task.difficulty + set defa…

…ult value to 3 not null

zou/app/models/task.py

@@ -33,11 +33,7 @@ class Task(db.Model, BaseMixin, SerializerMixin):
     description = db.Column(db.Text())
 
     priority = db.Column(db.Integer, default=0)
-    difficulty = db.Column(
-        db.Integer,
-        db.CheckConstraint("difficulty > 0 AND difficulty < 6"),
-        default=3,
-    )
+    difficulty = db.Column(db.Integer, default=3, nullable=False)
     duration = db.Column(db.Float, default=0)
     estimation = db.Column(db.Float, default=0)
     completion_rate = db.Column(db.Integer, default=0)
@@ -75,6 +71,9 @@ class Task(db.Model, BaseMixin, SerializerMixin):
         db.UniqueConstraint(
             "name", "project_id", "task_type_id", "entity_id", name="task_uc"
         ),
+        db.CheckConstraint(
+            "difficulty > 0 AND difficulty < 6", name="check_difficulty"
+        ),
     )
 
     def assignees_as_string(self):

zou/migrations/versions/8e67c183bed7_add_preference_fields.py

@@ -42,7 +42,12 @@ def upgrade():
 
     with op.batch_alter_table("task", schema=None) as batch_op:
         batch_op.add_column(
-            sa.Column("difficulty", sa.Integer(), nullable=True)
+            sa.Column(
+                "difficulty", sa.Integer(), nullable=False, server_default="3"
+            )
+        )
+        batch_op.create_check_constraint(
+            "check_difficulty", "difficulty > 0 AND difficulty < 6"
         )
 
     # ### end Alembic commands ###
@@ -51,6 +56,7 @@ def upgrade():
 def downgrade():
     # ### commands auto generated by Alembic - please adjust! ###
     with op.batch_alter_table("task", schema=None) as batch_op:
+        batch_op.drop_constraint("check_difficulty", type_="check")
         batch_op.drop_column("difficulty")
 
     with op.batch_alter_table("project", schema=None) as batch_op: