Copilot instructions

1---
2applyTo: "migrations/versions/*.py"
3---
4## Alembic Migrations
5 
6 
7### Default Content for New Non-Nullable Columns
8 
9To add a non-nullable column and set a specific value for all existing rows without a persistent server default:
10 
11```python
12# 1. Add the column as nullable (no default needed):
13op.add_column('distribution', sa.Column('default_campaign_ending_date', sa.DateTime(timezone=True), nullable=True))
14# 2. Update existing rows with your desired value (e.g., a specific datetime)
15op.execute("UPDATE distribution SET default_campaign_ending_date = %s", [datetime.utcnow()])
16# 3. Alter the column to non-nullable:
17op.alter_column('distribution', 'default_campaign_ending_date', nullable=False)
18```
19 
20### Record Backfill Operations
21 
22For migrations that include data mutation, and not only schema modifications, use this pattern to setup a session:
23 
24```python
25from alembic import op
26from sqlmodel import Session
27from activemodel.session_manager import global_session
28from app import log
29 
30def run_migration_helper():
31  pass
32 
33def upgrade() -> None:
34  session = Session(bind=op.get_bind())
35 
36  with global_session(session):
37      run_migration_helper()
38      flip_point_coordinates()
39      backfill_screening_host_data()
40 
41  # flush before running any other operations, otherwise not all changes will persist to the transaction
42  session.flush()
43```
44 
45However, if you don't need the business logic attached to the models, you can execute a query using `op.execute`:
46 
47```python
48op.execute(
49  TheModel.__table__.update().values({"a_field": "a_value"}) # type: ignore
50)
51```
52