diff --git a/backend/database/src/index.ts b/backend/database/src/index.ts
index 0d2721f..15056e8 100644
--- a/backend/database/src/index.ts
+++ b/backend/database/src/index.ts
@@ -110,12 +110,17 @@ export default {
 				const body = await request.json()
 				const { type, name, userId, visibility } = initSchema.parse(body)
 
-				const allSandboxes = await db.select().from(sandbox).all()
-				if (allSandboxes.length >= 8) {
-					return new Response("You reached the maximum # of sandboxes.", {
-						status: 400,
-					})
-				}
+				const userSandboxes = await db
+				.select()
+				.from(sandbox)
+				.where(eq(sandbox.userId, userId))
+				.all();
+			
+			if (userSandboxes.length >= 8) {
+				return new Response("You reached the maximum # of sandboxes.", {
+					status: 400,
+				});
+			}
 
 				const sb = await db
 					.insert(sandbox)
@@ -123,6 +128,12 @@ export default {
 					.returning()
 					.get()
 
+				// Create a new association record in the users_to_sandboxes table
+				await db
+					.insert(usersToSandboxes)
+					.values({ userId, sandboxId: sb.id, sharedOn: new Date() })
+					.get();
+
 				const initStorageRequest = new Request(
 					`${env.STORAGE_WORKER_URL}/api/init`,
 					{
diff --git a/backend/database/src/schema.ts b/backend/database/src/schema.ts
index 4403b96..4451e0f 100644
--- a/backend/database/src/schema.ts
+++ b/backend/database/src/schema.ts
@@ -31,8 +31,8 @@ export const sandbox = sqliteTable("sandbox", {
 	createdAt: integer("createdAt", { mode: "timestamp_ms" }),
 	userId: text("user_id")
 		.notNull()
-		.references(() => user.id),
-});
+		.references(() => user.id, { onDelete: "cascade" }),
+	});
 
 export type Sandbox = typeof sandbox.$inferSelect;