- 1. API with NestJS #1. Controllers, routing and the module structure
- 2. API with NestJS #2. Setting up a PostgreSQL database with TypeORM
- 3. API with NestJS #3. Authenticating users with bcrypt, Passport, JWT, and cookies
- 4. API with NestJS #4. Error handling and data validation
- 5. API with NestJS #5. Serializing the response with interceptors
- 6. API with NestJS #6. Looking into dependency injection and modules
- 7. API with NestJS #7. Creating relationships with Postgres and TypeORM
- 8. API with NestJS #8. Writing unit tests
- 9. API with NestJS #9. Testing services and controllers with integration tests
- 10. API with NestJS #10. Uploading public files to Amazon S3
- 11. API with NestJS #11. Managing private files with Amazon S3
- 12. API with NestJS #12. Introduction to Elasticsearch
- 13. API with NestJS #13. Implementing refresh tokens using JWT
- 14. API with NestJS #14. Improving performance of our Postgres database with indexes
- 15. API with NestJS #15. Defining transactions with PostgreSQL and TypeORM
- 16. API with NestJS #16. Using the array data type with PostgreSQL and TypeORM
- 17. API with NestJS #17. Offset and keyset pagination with PostgreSQL and TypeORM
- 18. API with NestJS #18. Exploring the idea of microservices
- 19. API with NestJS #19. Using RabbitMQ to communicate with microservices
- 20. API with NestJS #20. Communicating with microservices using the gRPC framework
- 21. API with NestJS #21. An introduction to CQRS
- 22. API with NestJS #22. Storing JSON with PostgreSQL and TypeORM
- 23. API with NestJS #23. Implementing in-memory cache to increase the performance
- 24. API with NestJS #24. Cache with Redis. Running the app in a Node.js cluster
- 25. API with NestJS #25. Sending scheduled emails with cron and Nodemailer
- 26. API with NestJS #26. Real-time chat with WebSockets
- 27. API with NestJS #27. Introduction to GraphQL. Queries, mutations, and authentication
- 28. API with NestJS #28. Dealing in the N + 1 problem in GraphQL
- 29. API with NestJS #29. Real-time updates with GraphQL subscriptions
- 30. API with NestJS #30. Scalar types in GraphQL
- 31. API with NestJS #31. Two-factor authentication
- 32. API with NestJS #32. Introduction to Prisma with PostgreSQL
- 33. API with NestJS #33. Managing PostgreSQL relationships with Prisma
- 34. API with NestJS #34. Handling CPU-intensive tasks with queues
- 35. API with NestJS #35. Using server-side sessions instead of JSON Web Tokens
- 36. API with NestJS #36. Introduction to Stripe with React
- 37. API with NestJS #37. Using Stripe to save credit cards for future use
- 38. API with NestJS #38. Setting up recurring payments via subscriptions with Stripe
- 39. API with NestJS #39. Reacting to Stripe events with webhooks
- 40. API with NestJS #40. Confirming the email address
- 41. API with NestJS #41. Verifying phone numbers and sending SMS messages with Twilio
- 42. API with NestJS #42. Authenticating users with Google
- 43. API with NestJS #43. Introduction to MongoDB
- 44. API with NestJS #44. Implementing relationships with MongoDB
- 45. API with NestJS #45. Virtual properties with MongoDB and Mongoose
- 46. API with NestJS #46. Managing transactions with MongoDB and Mongoose
- 47. API with NestJS #47. Implementing pagination with MongoDB and Mongoose
- 48. API with NestJS #48. Definining indexes with MongoDB and Mongoose
- 49. API with NestJS #49. Updating with PUT and PATCH with MongoDB and Mongoose
- 50. API with NestJS #50. Introduction to logging with the built-in logger and TypeORM
- 51. API with NestJS #51. Health checks with Terminus and Datadog
- 52. API with NestJS #52. Generating documentation with Compodoc and JSDoc
- 53. API with NestJS #53. Implementing soft deletes with PostgreSQL and TypeORM
- 54. API with NestJS #54. Storing files inside a PostgreSQL database
- 55. API with NestJS #55. Uploading files to the server
- 56. API with NestJS #56. Authorization with roles and claims
- 57. API with NestJS #57. Composing classes with the mixin pattern
- 58. API with NestJS #58. Using ETag to implement cache and save bandwidth
- 59. API with NestJS #59. Introduction to a monorepo with Lerna and Yarn workspaces
- 60. API with NestJS #60. The OpenAPI specification and Swagger
- 61. API with NestJS #61. Dealing with circular dependencies
- 62. API with NestJS #62. Introduction to MikroORM with PostgreSQL
- 63. API with NestJS #63. Relationships with PostgreSQL and MikroORM
- 64. API with NestJS #64. Transactions with PostgreSQL and MikroORM
- 65. API with NestJS #65. Implementing soft deletes using MikroORM and filters
- 66. API with NestJS #66. Improving PostgreSQL performance with indexes using MikroORM
- 67. API with NestJS #67. Migrating to TypeORM 0.3
- 68. API with NestJS #68. Interacting with the application through REPL
- 69. API with NestJS #69. Database migrations with TypeORM
- 70. API with NestJS #70. Defining dynamic modules
- 71. API with NestJS #71. Introduction to feature flags
- 72. API with NestJS #72. Working with PostgreSQL using raw SQL queries
- 73. API with NestJS #73. One-to-one relationships with raw SQL queries
- 74. API with NestJS #74. Designing many-to-one relationships using raw SQL queries
- 75. API with NestJS #75. Many-to-many relationships using raw SQL queries
- 76. API with NestJS #76. Working with transactions using raw SQL queries
- 77. API with NestJS #77. Offset and keyset pagination with raw SQL queries
- 78. API with NestJS #78. Generating statistics using aggregate functions in raw SQL
- 79. API with NestJS #79. Implementing searching with pattern matching and raw SQL
- 80. API with NestJS #80. Updating entities with PUT and PATCH using raw SQL queries
- 81. API with NestJS #81. Soft deletes with raw SQL queries
- 82. API with NestJS #82. Introduction to indexes with raw SQL queries
- 83. API with NestJS #83. Text search with tsvector and raw SQL
- 84. API with NestJS #84. Implementing filtering using subqueries with raw SQL
- 85. API with NestJS #85. Defining constraints with raw SQL
- 86. API with NestJS #86. Logging with the built-in logger when using raw SQL
- 87. API with NestJS #87. Writing unit tests in a project with raw SQL
- 88. API with NestJS #88. Testing a project with raw SQL using integration tests
- 89. API with NestJS #89. Replacing Express with Fastify
- 90. API with NestJS #90. Using various types of SQL joins
- 91. API with NestJS #91. Dockerizing a NestJS API with Docker Compose
- 92. API with NestJS #92. Increasing the developer experience with Docker Compose
- 93. API with NestJS #93. Deploying a NestJS app with Amazon ECS and RDS
- 94. API with NestJS #94. Deploying multiple instances on AWS with a load balancer
- 95. API with NestJS #95. CI/CD with Amazon ECS and GitHub Actions
- 96. API with NestJS #96. Running unit tests with CI/CD and GitHub Actions
- 97. API with NestJS #97. Introduction to managing logs with Amazon CloudWatch
- 98. API with NestJS #98. Health checks with Terminus and Amazon ECS
- 99. API with NestJS #99. Scaling the number of application instances with Amazon ECS
- 100. API with NestJS #100. The HTTPS protocol with Route 53 and AWS Certificate Manager
- 101. API with NestJS #101. Managing sensitive data using the AWS Secrets Manager
- 102. API with NestJS #102. Writing unit tests with Prisma
- 103. API with NestJS #103. Integration tests with Prisma
- 104. API with NestJS #104. Writing transactions with Prisma
- 105. API with NestJS #105. Implementing soft deletes with Prisma and middleware
- 106. API with NestJS #106. Improving performance through indexes with Prisma
- 107. API with NestJS #107. Offset and keyset pagination with Prisma
- 108. API with NestJS #108. Date and time with Prisma and PostgreSQL
- 109. API with NestJS #109. Arrays with PostgreSQL and Prisma
- 110. API with NestJS #110. Managing JSON data with PostgreSQL and Prisma
- 111. API with NestJS #111. Constraints with PostgreSQL and Prisma
- 112. API with NestJS #112. Serializing the response with Prisma
- 113. API with NestJS #113. Logging with Prisma
- 114. API with NestJS #114. Modifying data using PUT and PATCH methods with Prisma
- 115. API with NestJS #115. Database migrations with Prisma
- 116. API with NestJS #116. REST API versioning
- 117. API with NestJS #117. CORS – Cross-Origin Resource Sharing
- 118. API with NestJS #118. Uploading and streaming videos
- 119. API with NestJS #119. Type-safe SQL queries with Kysely and PostgreSQL
- 120. API with NestJS #120. One-to-one relationships with the Kysely query builder
- 121. API with NestJS #121. Many-to-one relationships with PostgreSQL and Kysely
- 122. API with NestJS #122. Many-to-many relationships with Kysely and PostgreSQL
- 123. API with NestJS #123. SQL transactions with Kysely
- 124. API with NestJS #124. Handling SQL constraints with Kysely
- 125. API with NestJS #125. Offset and keyset pagination with Kysely
- 126. API with NestJS #126. Improving the database performance with indexes and Kysely
- 127. API with NestJS #127. Arrays with PostgreSQL and Kysely
- 128. API with NestJS #128. Managing JSON data with PostgreSQL and Kysely
- 129. API with NestJS #129. Implementing soft deletes with SQL and Kysely
- 130. API with NestJS #130. Avoiding storing sensitive information in API logs
- 131. API with NestJS #131. Unit tests with PostgreSQL and Kysely
- 132. API with NestJS #132. Handling date and time in PostgreSQL with Kysely
- 133. API with NestJS #133. Introducing database normalization with PostgreSQL and Prisma
- 134. API with NestJS #134. Aggregating statistics with PostgreSQL and Prisma
- 135. API with NestJS #135. Referential actions and foreign keys in PostgreSQL with Prisma
- 136. API with NestJS #136. Raw SQL queries with Prisma and PostgreSQL range types
- 137. API with NestJS #137. Recursive relationships with Prisma and PostgreSQL
- 138. API with NestJS #138. Filtering records with Prisma
- 139. API with NestJS #139. Using UUID as primary keys with Prisma and PostgreSQL
- 140. API with NestJS #140. Using multiple PostgreSQL schemas with Prisma
- 141. API with NestJS #141. Getting distinct records with Prisma and PostgreSQL
- 142. API with NestJS #142. A video chat with WebRTC and React
- 143. API with NestJS #143. Optimizing queries with views using PostgreSQL and Kysely
- 144. API with NestJS #144. Creating CLI applications with the Nest Commander
- 145. API with NestJS #145. Securing applications with Helmet
- 146. API with NestJS #146. Polymorphic associations with PostgreSQL and Prisma
- 147. API with NestJS #147. The data types to store money with PostgreSQL and Prisma
- 148. API with NestJS #148. Understanding the injection scopes
- 149. API with NestJS #149. Introduction to the Drizzle ORM with PostgreSQL
- 150. API with NestJS #150. One-to-one relationships with the Drizzle ORM
- 151. API with NestJS #151. Implementing many-to-one relationships with Drizzle ORM
- 152. API with NestJS #152. SQL constraints with the Drizzle ORM
- 153. API with NestJS #153. SQL transactions with the Drizzle ORM
- 154. API with NestJS #154. Many-to-many relationships with Drizzle ORM and PostgreSQL
- 155. API with NestJS #155. Offset and keyset pagination with the Drizzle ORM
- 156. API with NestJS #156. Arrays with PostgreSQL and the Drizzle ORM
- 157. API with NestJS #157. Handling JSON data with PostgreSQL and the Drizzle ORM
- 158. API with NestJS #158. Soft deletes with the Drizzle ORM
- 159. API with NestJS #159. Date and time with PostgreSQL and the Drizzle ORM
- 160. API with NestJS #160. Using views with the Drizzle ORM and PostgreSQL
- 161. API with NestJS #161. Generated columns with the Drizzle ORM and PostgreSQL
- 162. API with NestJS #162. Identity columns with the Drizzle ORM and PostgreSQL
- 163. API with NestJS #163. Full-text search with the Drizzle ORM and PostgreSQL
- 164. API with NestJS #164. Improving the performance with indexes using Drizzle ORM
- 165. API with NestJS #165. Time intervals with the Drizzle ORM and PostgreSQL
- 166. API with NestJS #166. Logging with the Drizzle ORM
- 167. API with NestJS #167. Unit tests with the Drizzle ORM
- 168. API with NestJS #168. Integration tests with the Drizzle ORM
- 169. API with NestJS #169. Unique IDs with UUIDs using Drizzle ORM and PostgreSQL
- 170. API with NestJS #170. Polymorphic associations with PostgreSQL and Drizzle ORM
- 171. API with NestJS #171. Recursive relationships with Drizzle ORM and PostgreSQL
- 172. API with NestJS #172. Database normalization with Drizzle ORM and PostgreSQL
- 173. API with NestJS #173. Storing money with Drizzle ORM and PostgreSQL
- 174. API with NestJS #174. Multiple PostgreSQL schemas with Drizzle ORM
- 175. API with NestJS #175. PUT and PATCH requests with PostgreSQL and Drizzle ORM
- 176. API with NestJS #176. Database migrations with the Drizzle ORM
- 177. API with NestJS #177. Response serialization with the Drizzle ORM
- 178. API with NestJS #178. Storing files inside of a PostgreSQL database with Drizzle
- 179. API with NestJS #179. Pattern matching search with Drizzle ORM and PostgreSQL
- 180. API with NestJS #180. Organizing Drizzle ORM schema with PostgreSQL
Managing relationships between tables is a significant part of dealing with SQL databases. In this article, we continue learning to use Drizzle ORM with NestJS and implement many-to-one relationships.
Check out this repository if you want to see the full code from this article.
The many-to-one relationship
With many-to-one relationships, a row from the first table can be connected to multiple rows in the second table. What’s crucial is that the row from the second table can relate to just one row from the first table.
A great example is an article that can have a single author. On the other hand, a user can be an author of multiple articles. To implement that, we need to store the author’s ID in the articles table. This way, the author_id will act as a foreign key and match rows from the users table.
When defining a foreign key, PostgreSQL creates a foreign key constraint to ensure our database stays consistent. This prevents us from having an author_id value that points to a user that does not exist. This means that we can’t:
- delete a user that’s an author of an article
- first, we would have to delete the article or change its author
- alternatively, we could use the CASCADE option in PostgreSQL to delete all articles the user is an author of
- create an article with the author_id that does not point to a valid user
- update existing articles and change the author_id to point to a user that does not exist
Creating a many-to-one relationship with the Drizzle ORM
In one of the previous parts of this series, we created the basics of the users and articles tables. Let’s add the author_id column to our schema.
database-schema.ts
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import { serial, text, integer, pgTable } from 'drizzle-orm/pg-core'; export const users = pgTable('users', { id: serial('id').primaryKey(), email: text('email').unique(), name: text('name'), password: text('password'), addressId: integer('address_id') .unique() .references(() => addresses.id), }); export const articles = pgTable('articles', { id: serial('id').primaryKey(), title: text('title'), content: text('content'), authorId: integer('author_id').references(() => users.id), }); // ... export const databaseSchema = { articles, addresses, users, usersAddressesRelation, }; |
Now, we can use the Drizzle ORM Kit to create a migration file.
Check out API with NestJS #149. Introduction to the Drizzle ORM with PostgreSQL to learn more about managing migrations with the Drizzle ORM Kit
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npx drizzle-kit generate --name add-author-id |
When we run the above command, Drizzle creates a SQL migration file.
0002_add-author-id.sql
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ALTER TABLE "articles" ADD COLUMN "author_id" integer;--> statement-breakpoint DO $$ BEGIN ALTER TABLE "articles" ADD CONSTRAINT "articles_author_id_users_id_fk" FOREIGN KEY ("author_id") REFERENCES "public"."users"("id") ON DELETE no action ON UPDATE no action; EXCEPTION WHEN duplicate_object THEN null; END $$; |
The last step is to run the migration.
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npx drizzle-kit migrate |
There is one crucial thing to consider here. The new column we added is not nullable. If we already have some articles in our database, adding a new non-nullable column without a default value will cause an error. If that’s the case for you, you can create a default user in your database and provide their ID as the value for the author_id in the existing articles.
One-to-one vs many-to-one
In the previous article, we created a one-to-one relationship.
database-schema.ts
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import { serial, integer, pgTable } from 'drizzle-orm/pg-core'; export const addresses = pgTable('addresses', { id: serial('id').primaryKey(), // ... }); export const users = pgTable('users', { id: serial('id').primaryKey(), // ... addressId: integer('address_id') .unique() .references(() => addresses.id), }); |
To ensure that a particular address belongs to only one user, we added the unique constraint.
However, when adding the author_id column, we don’t include the unique constraint. This allows multiple articles to have the same author.
Creating an article with an author
When creating articles, we should provide the author’s ID.
articles.service.ts
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import { Injectable } from '@nestjs/common'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { CreateArticleDto } from './dto/create-article.dto'; @Injectable() export class ArticlesService { constructor(private readonly drizzleService: DrizzleService) {} async create(article: CreateArticleDto, authorId: number) { const createdArticles = await this.drizzleService.db .insert(databaseSchema.articles) .values({ authorId, title: article.title, content: article.content, }) .returning(); return createdArticles.pop(); } // ... } |
What’s important is that we shouldn’t expect the author’s ID to be provided directly in the body of the POST request. Instead, we should get this data by decoding the JWT authentication token.
To learn more JWT tokens and authentication, check out API with NestJS #3. Authenticating users with bcrypt, Passport, JWT, and cookies
articles.controller.ts
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import { Body, Controller, Post, Req, UseGuards } from '@nestjs/common'; import { ArticlesService } from './articles.service'; import { CreateArticleDto } from './dto/create-article.dto'; import { JwtAuthenticationGuard } from '../authentication/jwt-authentication.guard'; import { RequestWithUser } from '../authentication/request-with-user.interface'; @Controller('articles') export class ArticlesController { constructor(private readonly articlesService: ArticlesService) {} @Post() @UseGuards(JwtAuthenticationGuard) create(@Body() article: CreateArticleDto, @Req() request: RequestWithUser) { return this.articlesService.create(article, request.user.id); } // ... } |
The RequestWithUser type extends the Request type from Express.
request-with-user.interface.ts
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import { Request } from 'express'; export interface RequestWithUser extends Request { user: { id: number; name: string; email: string; }; } |
Combining the article’s data and the author
Right now, when we fetch the details of a particular article, we only get the author’s ID.
Let’s change it to send the author’s details.
Making a join query
One solution would be to do a join query. In SQL databases, joins are used to combine rows from two or more tables.
The most basic type of join is the inner join, which returns records with matching rows in both tables. Since each article has an author, an inner join is a valid approach.
articles.service.ts
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import { Injectable, NotFoundException } from '@nestjs/common'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { eq } from 'drizzle-orm'; @Injectable() export class ArticlesService { constructor(private readonly drizzleService: DrizzleService) {} async getWithAuthor(articleId: number) { const allResults = await this.drizzleService.db .select() .from(databaseSchema.articles) .where(eq(databaseSchema.articles.id, articleId)) .innerJoin( databaseSchema.users, eq(databaseSchema.articles.authorId, databaseSchema.users.id), ); const result = allResults.pop(); if (!result) { throw new NotFoundException(); } return { ...result.articles, author: result.users, }; } // ... } |
We also need to use the getWithAuthor method in our controller.
articles.controller.ts
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import { Controller, Get, Param, ParseIntPipe } from '@nestjs/common'; import { ArticlesService } from './articles.service'; @Controller('articles') export class ArticlesController { constructor(private readonly articlesService: ArticlesService) {} @Get(':id') getById(@Param('id', ParseIntPipe) id: number) { return this.articlesService.getWithAuthor(id); } // ... } |
With this approach, we respond with the data of an article combined with the details of its author.
Using the Query API
Alternatively, we can use the Query API built into the Drizzle ORM to avoid doing the join query manually. To do that, we need to provide Drizzle with more details about the relationship between the users and articles.
database-schema.ts
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import { serial, text, integer, pgTable } from 'drizzle-orm/pg-core'; import { relations } from 'drizzle-orm'; // ... export const users = pgTable('users', { id: serial('id').primaryKey(), email: text('email').unique(), name: text('name'), password: text('password'), addressId: integer('address_id') .unique() .references(() => addresses.id), }); export const articles = pgTable('articles', { id: serial('id').primaryKey(), title: text('title'), content: text('content'), authorId: integer('author_id').references(() => users.id), }); export const articlesAuthorsRelation = relations(articles, ({ one }) => ({ author: one(users, { fields: [articles.authorId], references: [users.id], }), })); export const databaseSchema = { articles, addresses, users, usersAddressesRelation, articlesAuthorsRelation, }; |
Thanks to creating the articlesAuthorsRelation, we can now use the Query API to fetch articles and their authors.
articles.service.ts
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import { Injectable, NotFoundException } from '@nestjs/common'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { eq } from 'drizzle-orm'; @Injectable() export class ArticlesService { constructor(private readonly drizzleService: DrizzleService) {} async getWithAuthor(articleId: number) { const article = await this.drizzleService.db.query.articles.findFirst({ with: { author: true, }, where: eq(databaseSchema.articles.id, articleId), }); if (!article) { throw new NotFoundException(); } return article; } // ... } |
We can take it further and fetch both the author and their address.
articles.service.ts
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import { Injectable, NotFoundException } from '@nestjs/common'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { eq } from 'drizzle-orm'; @Injectable() export class ArticlesService { constructor(private readonly drizzleService: DrizzleService) {} async getWithAuthor(articleId: number) { const article = await this.drizzleService.db.query.articles.findFirst({ with: { author: { with: { address: true, }, }, }, where: eq(databaseSchema.articles.id, articleId), }); if (!article) { throw new NotFoundException(); } return article; } // ... } |
Under the hood, Drizzle ORM will make two join queries—one to retrieve the user and the other to retrieve their address.
Summary
In this article, we’ve explained the many-to-one relationship and implemented it using the Drizzle ORM and NestJS. When doing that, we learned how to combine data from two tables through SQL join queries and by using the Query API built into the Drizzle ORM.
We still have more to learn about relationships with PostgreSQL and Drizzle ORM, so stay tuned!