update migration + change where extent is saved

backend/app/alembic/versions/dc391733e10a_add_extent_to_gerrydb.py

@@ -10,93 +10,60 @@
 
 from alembic import op
 import sqlalchemy as sa
-from app.models import GerryDBTable
+from app.models import DistrictrMap
 
 # revision identifiers, used by Alembic.
 revision: str = "dc391733e10a"
 down_revision: Union[str, None] = "5ab466c5650a"
 branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+depends_on = ("167892041d95",)  # geometry col renaming
 
 
 def upgrade() -> None:
     # ### commands auto generated by Alembic - please adjust! ###
     # Make column nullable to avoid errors during initial insert
     op.add_column(
-        "gerrydbtable", sa.Column("extent", sa.ARRAY(sa.Float()), nullable=True)
+        "districtrmap", sa.Column("extent", sa.ARRAY(sa.Float()), nullable=True)
     )
 
     # Use a session to interact with the database
     bind = op.get_bind()
     Session = sa.orm.sessionmaker(bind=bind)
     session = Session()
 
-    # Step 1: Retrieve all table names from public.gerrydbtable
-    table_names = session.execute(sa.select(GerryDBTable.name)).scalars().all()
+    # retreive table names from the districtrmap parent_layer field
+    table_names = session.execute(sa.select(DistrictrMap.parent_layer)).scalars().all()
 
     if not table_names:
         raise ValueError("No matching table names found in the index table")
 
-    def column_exists(table_name, column_name):
-        column_check_query = sa.text(
-            f"""
-            SELECT EXISTS (
-                SELECT 1
-                FROM information_schema.columns
-                WHERE table_schema = 'gerrydb'
-                AND table_name = :table_name
-                AND column_name = :column_name
-            )
-        """
-        )
-        result = bind.execute(
-            column_check_query, {"table_name": table_name, "column_name": column_name}
-        ).scalar()
-        return result
-
     cases = []
     for table_name in table_names:
-        has_geometry = column_exists(table_name, "geometry")
-        has_geography = column_exists(table_name, "geography")
-
-        if has_geometry:
-            geom_column = "geometry"
-        elif has_geography:
-            geom_column = "geography"
-        # Add the CASE statement with the correct column name
-
-        if has_geometry or has_geography:
-            case = f"""
-            WHEN name = '{table_name}' THEN (
-                SELECT
-                    ARRAY[
-                        ST_XMin(ST_Extent(ST_Transform({geom_column}, 4326))),
-                        ST_YMin(ST_Extent(ST_Transform({geom_column}, 4326))),
-                        ST_XMax(ST_Extent(ST_Transform({geom_column}, 4326))),
-                        ST_YMax(ST_Extent(ST_Transform({geom_column}, 4326)))
-                    ]
-                FROM gerrydb."{table_name}"
-            )
-            """
-
-        else:
-            # just skip for now and return generic placeholder array
-            print(f"No geometry or geography column found in table '{table_name}'.")
-            case = f"""
-            WHEN name = '{table_name}' THEN ARRAY[0, 0, 0, 0]
-            """
-        cases.append(case)
+        case = f"""
+        WHEN districtrmap."parent_layer" = '{table_name}' THEN (
+            SELECT
+                ARRAY[
+                    ST_XMin(ST_Extent(ST_Transform(geometry, 4326))),
+                    ST_YMin(ST_Extent(ST_Transform(geometry, 4326))),
+                    ST_XMax(ST_Extent(ST_Transform(geometry, 4326))),
+                    ST_YMax(ST_Extent(ST_Transform(geometry, 4326)))
+                ]
+            FROM gerrydb."{table_name}", public.districtrmap
+            
+        )
+        """
 
+        cases.append(case)
     # Combine all cases into a single SQL statement
     case_statement = " ".join(cases)
-
     # Execute a single UPDATE statement
     update_query = sa.text(
         f"""
-        UPDATE gerrydbtable
+        UPDATE districtrmap
         SET extent = CASE
             {case_statement}
-            ELSE extent  -- Leave unchanged if no match; this should never happen
+        -- ELSE ARRAY[0, 0, 0, 0] if this fails, there is no
+        -- matching table from parent_layer and that's a problem
         END;
     """
     )
@@ -105,13 +72,13 @@ def column_exists(table_name, column_name):
 
     # Make the `extent` column non-nullable
     op.alter_column(
-        "gerrydbtable", "extent", existing_type=sa.ARRAY(sa.Float()), nullable=False
+        "districtrmap", "extent", existing_type=sa.ARRAY(sa.Float()), nullable=False
     )
 
     session.commit()
 
 
 def downgrade() -> None:
     # ### commands auto generated by Alembic - please adjust! ###
-    op.drop_column("gerrydbtable", "extent")
+    op.drop_column("districtrmap", "extent")
     # ### end Alembic commands ###

backend/app/models.py

@@ -64,9 +64,7 @@ class DistrictrMap(TimeStampMixin, SQLModel, table=True):
             String, ForeignKey("gerrydbtable.name"), default=None, nullable=True
         )
     )
-    extent: list[float] = Field(
-        sa_column=Column(ARRAY(Float), nullable=False)
-    )  # at the gdb table level and not the doc level
+    extent: list[float] = Field(sa_column=Column(ARRAY(Float), nullable=False))
     # schema? will need to contrain the schema
     # where does this go?
     # when you create the view, pull the columns that you need