text: CREATE TABLE IF NOT EXISTS "users" (
    "id" SERIAL PRIMARY KEY,
    "username" TEXT,
    "password" TEXT,
    "salt" TEXT
  );
  
  CREATE TABLE IF NOT EXISTS "canvasses" (
    "id" SERIAL PRIMARY KEY,
    "title" TEXT,
    "owner_id" INTEGER
  );
  
  CREATE TABLE IF NOT EXISTS "notes" (
    "id" SERIAL PRIMARY KEY,
    "title" varchar,
    "owner_id" INTEGER,
    "body" TEXT
  );
  
  CREATE TABLE IF NOT EXISTS "placements" (
    "id" SERIAL PRIMARY KEY,
    "notes_id" INTEGER NOT NULL,
    "canvas_id" INTEGER NOT NULL,
    "coordinates" POINT
  );
  
  ALTER TABLE "canvasses" ADD FOREIGN KEY ("owner_id") REFERENCES "users" ("id") ON DELETE CASCADE;
  
  ALTER TABLE "notes" ADD FOREIGN KEY ("owner_id") REFERENCES "users" ("id") ON DELETE CASCADE;
  
  ALTER TABLE "placements" ADD FOREIGN KEY ("notes_id") REFERENCES "notes" ("id") ON DELETE CASCADE;
  
  ALTER TABLE "placements" ADD FOREIGN KEY ("canvas_id") REFERENCES "canvasses" ("id") ON DELETE CASCADE;
  