CREATE TABLE "Lot" ( "LotNumber" SERIAL PRIMARY KEY, "CreateDate" date, "Cost_Of_Materials" float ); CREATE TABLE "Lot_Raw_Materials" ( "id" SERIAL PRIMARY KEY ); CREATE TABLE "Raw_Materials" ( "material_id" SERIAL PRIMARY KEY, "UniCost" float, "type" varchar ); CREATE TABLE "Production_Units" ( "serial" SERIAL PRIMARY KEY, "exactWeight" float, "ProductType" varchar, "ProductDesc" float ); ALTER TABLE "Lot" ADD FOREIGN KEY ("LotNumber") REFERENCES "Lot_Raw_Materials" ("id"); ALTER TABLE "Raw_Materials" ADD FOREIGN KEY ("material_id") REFERENCES "Lot_Raw_Materials" ("id"); ALTER TABLE "Production_Units" ADD FOREIGN KEY ("serial") REFERENCES "Lot" ("LotNumber");