-- Primary material (brick/clay tile, slate, steel/metal, timber, stone, glass, concrete, -- natural-green or thatch, asphalt or other) ALTER TABLE buildings DROP COLUMN IF EXISTS construction_core_material; --Secondary material ALTER TABLE buildings DROP COLUMN IF EXISTS construction_secondary_materials; --Primary roof material ALTER TABLE buildings DROP COLUMN IF EXISTS construction_roof_covering; DROP TYPE IF EXISTS construction_materials; DROP TYPE IF EXISTS roof_covering;