Holy db migrations batman

alembic/versions/2025_12_03_0950-694d52a883c3_remove_composite_fk_from_conversions.py

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+"""remove_composite_fk_from_conversions
+
+Revision ID: 694d52a883c3
+Revises: b50c0f45030a
+Create Date: 2025-12-03 09:50:18.506030
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '694d52a883c3'
+down_revision: Union[str, Sequence[str], None] = 'b50c0f45030a'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(op.f('conversions_hotel_id_guest_id_fkey'), 'conversions', type_='foreignkey')
+
+    # Rename hotel_code to hotel_id (preserving data) and add FK to hotels
+    op.add_column('reservations', sa.Column('hotel_id', sa.String(), nullable=True))
+    op.execute('UPDATE reservations SET hotel_id = hotel_code')
+    op.drop_column('reservations', 'hotel_code')
+
+    # Add FK constraint without immediate validation (NOT VALID)
+    # This allows existing rows with non-existent hotel_ids to remain
+    # Future inserts/updates will still be validated
+    op.execute(
+        'ALTER TABLE reservations ADD CONSTRAINT fk_reservations_hotel_id_hotels '
+        'FOREIGN KEY (hotel_id) REFERENCES hotels (hotel_id) ON DELETE CASCADE NOT VALID'
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    # Drop FK and rename hotel_id back to hotel_code (preserving data)
+    op.drop_constraint(op.f('fk_reservations_hotel_id_hotels'), 'reservations', type_='foreignkey')
+    op.add_column('reservations', sa.Column('hotel_code', sa.VARCHAR(), autoincrement=False, nullable=True))
+    op.execute('UPDATE reservations SET hotel_code = hotel_id')
+    op.drop_column('reservations', 'hotel_id')
+
+    op.create_foreign_key(op.f('conversions_hotel_id_guest_id_fkey'), 'conversions', 'conversion_guests', ['hotel_id', 'guest_id'], ['hotel_id', 'guest_id'], ondelete='SET NULL')
+    # ### end Alembic commands ###