add parent generic asset

Signed-off-by: Victor Garcia Reolid <victor@seita.nl>

flexmeasures/data/migrations/versions/40d6c8e4be94_add_parent_asset_field.py

@@ -0,0 +1,29 @@
+"""empty message
+
+Revision ID: 40d6c8e4be94
+Revises: 2ac7fb39ce0c
+Create Date: 2023-09-19 17:05:00.020779
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "40d6c8e4be94"
+down_revision = "2ac7fb39ce0c"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column(
+        "generic_asset",
+        sa.Column(
+            "parent_generic_asset_id", sa.INTEGER, sa.ForeignKey("generic_asset.id")
+        ),
+    )
+
+
+def downgrade():
+    op.drop_column("generic_asset", "parent_generic_asset_id")

flexmeasures/data/models/generic_assets.py

@@ -54,10 +54,17 @@ class GenericAsset(db.Model, AuthModelMixin):
     latitude = db.Column(db.Float, nullable=True)
     longitude = db.Column(db.Float, nullable=True)
     attributes = db.Column(MutableDict.as_mutable(db.JSON), nullable=False, default={})
+    parent_generic_asset_id = db.Column(
+        db.Integer, db.ForeignKey("generic_asset.id"), nullable=True
+    )
+    parent_generic_asset = db.relationship(
+        "GenericAsset", remote_side=[id], backref="child_generic_assets"
+    )
 
     generic_asset_type_id = db.Column(
         db.Integer, db.ForeignKey("generic_asset_type.id"), nullable=False
     )
+
     generic_asset_type = db.relationship(
         "GenericAssetType",
         foreign_keys=[generic_asset_type_id],