CREATE TABLE "tiles" (
"id" INTEGER NOT NULL,
"world_id" INTEGER NOT NULL DEFAULT 0,
"house_id" INTEGER NOT NULL,
"x" INTEGER NOT NULL,
"y" INTEGER NOT NULL,
"z" INTEGER NOT NULL,
UNIQUE ("id", "world_id"),
FOREIGN KEY ("house_id", "world_id") REFERENCES "houses" ("id", "world_id")
);