Chapter 07 · Firebase Data Connect
Subchapter 7.15
examples.mdMarkdown15 KBView on GitHub
Complete, working examples for common SQL Connect use cases.
A complete schema for a movie database with reviews, actors, and user authentication.
# schema.gql
# Users
type User @table(key: "uid") {
uid: String! @default(expr: "auth.uid")
email: String! @unique
displayName: String
createdAt: Timestamp! @default(expr: "request.time")
}
# Movies
type Movie @table {
id: UUID! @default(expr: "uuidV4()")
title: String!
releaseYear: Int
genre: String @index
rating: Float
description: String
posterUrl: String
createdAt: Timestamp! @default(expr: "request.time")
}
# Movie metadata (one-to-one)
type MovieMetadata @table {
movie: Movie! @unique
director: String
runtime: Int
budget: Int64
}
# Actors
type Actor @table {
id: UUID! @default(expr: "uuidV4()")
name: String!
birthDate: Date
}
# Movie-Actor relationship (many-to-many)
type MovieActor @table(key: ["movie", "actor"]) {
movie: Movie!
actor: Actor!
role: String! # "lead" or "supporting"
character: String
}
# Reviews (user-owned)
type Review @table @unique(fields: ["movie", "user"]) {
id: UUID! @default(expr: "uuidV4()")
movie: Movie!
user: User!
rating: Int!
text: String
createdAt: Timestamp! @default(expr: "request.time")
}# queries.gql
# Public: List movies with filtering
query ListMovies($genre: String, $minRating: Float, $limit: Int)
@auth(level: PUBLIC) {
movies(
where: {
genre: { eq: $genre },
rating: { ge: $minRating }
},
orderBy: [{ rating: DESC }],
limit: $limit
) {
id title genre rating releaseYear posterUrl
}
}
# Public: Get movie with full details
query GetMovie($id: UUID!) @auth(level: PUBLIC) {
movie(id: $id) {
id title genre rating releaseYear description
metadata: movieMetadata_on_movie { director runtime }
actors: actors_via_MovieActor { name }
reviews: reviews_on_movie(orderBy: [{ createdAt: DESC }], limit: 10) {
rating text createdAt
user { displayName }
}
}
}
# User: Get my reviews
query MyReviews @auth(level: USER) {
reviews(where: { user: { uid: { eq_expr: "auth.uid" }}}) {
id rating text createdAt
movie { id title posterUrl }
}
}# mutations.gql
# User: Create/update profile on first login
mutation UpsertUser($email: String!, $displayName: String) @auth(level: USER) {
user_upsert(data: {
uid_expr: "auth.uid",
email: $email,
displayName: $displayName
})
}
# User: Add review (one per movie per user)
mutation AddReview($movieId: UUID!, $rating: Int!, $text: String)
@auth(level: USER) {
review_upsert(data: {
movie: { id: $movieId },
user: { uid_expr: "auth.uid" },
rating: $rating,
text: $text
})
}
# User: Delete my review
mutation DeleteReview($id: UUID!) @auth(level: USER) {
review_delete(
first: { where: {
id: { eq: $id },
user: { uid: { eq_expr: "auth.uid" }}
}}
)
}# queries.gql (realtime additions)
# Auto-refresh: this single-entity lookup refreshes automatically
# when any mutation modifies this specific movie. No @refresh needed.
query GetMovie($id: UUID!) @auth(level: PUBLIC) {
movie(id: $id) {
id title genre rating releaseYear description
metadata: movieMetadata_on_movie { director runtime }
reviews: reviews_on_movie(orderBy: [{ createdAt: DESC }], limit: 10) {
rating text createdAt
user { displayName }
}
}
}
# Event-driven: Simple refresh when any movie is added
query ListMoviesSimple @auth(level: PUBLIC) @refresh(onMutationExecuted: { operation: "AddMovie" }) {
movies { id title }
}
# Counterpart mutation for ListMoviesSimple
mutation AddMovie($title: String!) @auth(level: USER) {
movie_insert(data: { title: $title })
}
# Event-driven: Refresh only when a movie of the same genre is added
# Demonstrates the use of 'condition' and 'mutation.variables'
query ListMoviesByGenre($genre: String!) @auth(level: PUBLIC)
@refresh(onMutationExecuted: {
operation: "AddMovieWithGenre",
condition: "mutation.variables.genre == request.variables.genre"
}) {
movies(where: { genre: { eq: $genre } }) { id title }
}
# Counterpart mutation for ListMoviesByGenre
mutation AddMovieWithGenre($title: String!, $genre: String!) @auth(level: USER) {
movie_insert(data: { title: $title, genre: $genre })
}
# Event-driven: Refresh user profile when updated
# Demonstrates condition based on auth context
query MyProfile @auth(level: USER)
@refresh(onMutationExecuted: {
operation: "UpdateProfile",
condition: "mutation.auth.uid == request.auth.uid"
}) {
user(uid_expr: "auth.uid") { id name }
}
# Counterpart mutation for MyProfile
mutation UpdateProfile($name: String!) @auth(level: USER) {
user_update(id_expr: "auth.uid", data: { name: $name })
}
# Time-based: live leaderboard refreshing every 30 seconds
query MovieLeaderboard
@auth(level: PUBLIC)
@refresh(every: { seconds: 30 }) {
movies(orderBy: [{ rating: DESC }], limit: 10) {
id title rating
}
}import { listMoviesRef, movieLeaderboardRef } from '@movie-app/dataconnect';
import { subscribe } from 'firebase/data-connect';
// Subscribe to movie list — refreshes when AddReview mutation runs
const unsubMovies = subscribe(listMoviesRef({ genre: 'Action' }), {
onNext: (result) => updateMovieList(result.data.movies),
onError: (error) => console.error(error)
});
// Subscribe to leaderboard — refreshes every 30 seconds
const unsubLeaderboard = subscribe(movieLeaderboardRef(), {
onNext: (result) => updateLeaderboard(result.data.movies),
onError: (error) => console.error(error)
});
// Cleanup
// unsubMovies();
// unsubLeaderboard();Products, orders, and cart management with user authentication.
# schema.gql
type User @table(key: "uid") {
uid: String! @default(expr: "auth.uid")
email: String! @unique
name: String
shippingAddress: String
}
type Product @table {
id: UUID! @default(expr: "uuidV4()")
name: String! @index
description: String
price: Float!
stock: Int! @default(value: 0)
category: String @index
imageUrl: String
}
type CartItem @table(key: ["user", "product"]) {
user: User!
product: Product!
quantity: Int!
}
enum OrderStatus {
PENDING
PAID
SHIPPED
DELIVERED
CANCELLED
}
type Order @table {
id: UUID! @default(expr: "uuidV4()")
user: User!
status: OrderStatus! @default(value: PENDING)
total: Float!
shippingAddress: String!
createdAt: Timestamp! @default(expr: "request.time")
}
type OrderItem @table {
id: UUID! @default(expr: "uuidV4()")
order: Order!
product: Product!
quantity: Int!
priceAtPurchase: Float!
}# Public: Browse products
query ListProducts($category: String, $search: String) @auth(level: PUBLIC) {
products(where: {
category: { eq: $category },
name: { contains: $search },
stock: { gt: 0 }
}) {
id name price stock imageUrl
}
}
# User: View cart
query MyCart @auth(level: USER) {
cartItems(where: { user: { uid: { eq_expr: "auth.uid" }}}) {
quantity
product { id name price imageUrl stock }
}
}
# User: Add to cart
mutation AddToCart($productId: UUID!, $quantity: Int!) @auth(level: USER) {
cartItem_upsert(data: {
user: { uid_expr: "auth.uid" },
product: { id: $productId },
quantity: $quantity
})
}
# User: Checkout (transactional)
mutation Checkout($shippingAddress: String!)
@auth(level: USER)
@transaction {
# Query cart items
query @redact {
cartItems(where: { user: { uid: { eq_expr: "auth.uid" }}})
@check(expr: "this.size() > 0", message: "Cart is empty") {
quantity
product { id price }
}
}
# Create order (in real app, calculate total from cart)
order_insert(data: {
user: { uid_expr: "auth.uid" },
shippingAddress: $shippingAddress,
total: 0 # Calculate in app logic
})
}Multi-author blog with role-based permissions.
# schema.gql
type User @table(key: "uid") {
uid: String! @default(expr: "auth.uid")
email: String! @unique
name: String!
bio: String
}
enum UserRole {
VIEWER
AUTHOR
EDITOR
ADMIN
}
type BlogPermission @table(key: ["user"]) {
user: User!
role: UserRole! @default(value: VIEWER)
}
enum PostStatus {
DRAFT
PUBLISHED
ARCHIVED
}
type Post @table {
id: UUID! @default(expr: "uuidV4()")
author: User!
title: String! @searchable
content: String! @searchable
status: PostStatus! @default(value: DRAFT)
publishedAt: Timestamp
createdAt: Timestamp! @default(expr: "request.time")
updatedAt: Timestamp! @default(expr: "request.time")
}
type Comment @table {
id: UUID! @default(expr: "uuidV4()")
post: Post!
author: User!
content: String!
createdAt: Timestamp! @default(expr: "request.time")
}# Public: Read published posts
query PublishedPosts @auth(level: PUBLIC) {
posts(
where: { status: { eq: PUBLISHED }},
orderBy: [{ publishedAt: DESC }]
) {
id title content publishedAt
author { name }
}
}
# Author+: Create post
mutation CreatePost($title: String!, $content: String!)
@auth(level: USER)
@transaction {
# Check user is at least AUTHOR
query @redact {
blogPermission(key: { user: { uid_expr: "auth.uid" }})
@check(expr: "this != null", message: "No permission record") {
role @check(expr: "this in ['AUTHOR', 'EDITOR', 'ADMIN']", message: "Must be author+")
}
}
post_insert(data: {
author: { uid_expr: "auth.uid" },
title: $title,
content: $content
})
}
# Editor+: Publish any post
mutation PublishPost($id: UUID!)
@auth(level: USER)
@transaction {
query @redact {
blogPermission(key: { user: { uid_expr: "auth.uid" }}) {
role @check(expr: "this in ['EDITOR', 'ADMIN']", message: "Must be editor+")
}
}
post_update(id: $id, data: {
status: PUBLISHED,
publishedAt_expr: "request.time"
})
}
# Admin: Grant role
mutation GrantRole($userUid: String!, $role: UserRole!)
@auth(level: USER)
@transaction {
query @redact {
blogPermission(key: { user: { uid_expr: "auth.uid" }}) {
role @check(expr: "this == 'ADMIN'", message: "Must be admin")
}
}
blogPermission_upsert(data: {
user: { uid: $userUid },
role: $role
})
}For scenarios where standard GraphQL cannot express the required database logic, use Native SQL.
query GetMoviesByGenre($genre: String!, $limit: Int!) @auth(level: PUBLIC) {
movies: _select(
sql: """
SELECT id, title, release_year, rating
FROM movie
WHERE genre = $1
ORDER BY release_year DESC
LIMIT $2
""",
params: [$genre, $limit]
)
}mutation UpdateMovieRating($movieId: UUID!, $newRating: Float!) @auth(level: USER) {
_execute(
sql: """
UPDATE movie
SET rating = $2
WHERE id = $1
""",
params: [$movieId, $newRating]
)
}query GetMoviesRankedByRating @auth(level: PUBLIC) {
_select(
sql: """
SELECT
id,
title,
rating,
RANK() OVER (ORDER BY rating DESC) as rank
FROM movie
WHERE rating IS NOT NULL
LIMIT 20
""",
params: []
)
}mutation UpdateMyReviewText($movieId: UUID!, $newText: String!) @auth(level: USER) {
updatedReview: _executeReturningFirst(
sql: """
UPDATE review
SET text = $2
WHERE movie_id = $1 AND user_uid = $3
RETURNING movie_id, user_uid, rating, text
""",
params: [$movieId, $newText, {_expr: "auth.uid"}]
)
}Note: Data-modifying CTEs are only supported by _execute, not
_executeReturning.
mutation CreateMovieCTE($movieId: UUID!, $userUid: String!, $reviewId: UUID!) @auth(level: USER) {
_execute(
sql: """
WITH
new_user AS (
INSERT INTO "user" (uid, email, display_name)
VALUES ($2, 'auto@example.com', 'Auto-Generated User')
ON CONFLICT (uid) DO NOTHING
RETURNING uid
),
movie AS (
INSERT INTO movie (id, title, poster_url, release_year, genre)
VALUES ($1, 'Auto-Generated Movie', 'https://placeholder.com', 2025, 'Sci-Fi')
ON CONFLICT (id) DO NOTHING
RETURNING id
)
INSERT INTO review (id, movie_id, user_uid, rating, text, created_at)
VALUES (
$3,
$1,
$2,
5,
'Good!',
NOW()
)
""",
params: [$movieId, $userUid, $reviewId]
)
}Because mutation operations are single requests, you can chain multiple
_execute commands within a @transaction to ensure they all succeed or fail
together.
mutation SafeTransfer($from: UUID!, $to: UUID!, $amount: Float!) @auth(level: USER) @transaction {
deduct: _execute(
sql: "UPDATE account SET balance = balance - $2 WHERE id = $1",
params: [$from, $amount]
)
add: _execute(
sql: "UPDATE account SET balance = balance + $2 WHERE id = $1",
params: [$to, $amount]
)
}Prerequisite: You must enable the extension on your underlying Cloud SQL instance by connecting to your database as the postgres user and running:
CREATE EXTENSION IF NOT EXISTS postgis;query GetNearbyActiveRestaurants($userLong: Float!, $userLat: Float!, $maxDistanceMeters: Float!) @auth(level: USER) {
nearby: _select(
sql: """
SELECT
id,
name,
tags,
ST_Distance(
ST_MakePoint((metadata->>'longitude')::float, (metadata->>'latitude')::float)::geography,
ST_MakePoint($1, $2)::geography
) as distance_meters
FROM restaurant
WHERE active = true
AND metadata ? 'longitude' AND metadata ? 'latitude'
AND ST_DWithin(
ST_MakePoint((metadata->>'longitude')::float, (metadata->>'latitude')::float)::geography,
ST_MakePoint($1, $2)::geography,
$3
)
ORDER BY distance_meters ASC
LIMIT 10
""",
params: [$userLong, $userLat, $maxDistanceMeters]
)
}After running the query using a client SDK, the result will be in
data.nearby.