- 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
When building a database, the tables we set up often connect to each other. Managing these relationships is one of the crucial parts of working with databases.
In the previous article, we learned how to use NestJS with Drizzle to set up a simple project with PostgreSQL. This time, we go further and write more complex code that involves the one-to-one relationship.
You can find the code from this article in this repository.
What is a one-to-one relationship?
When designing a database with users and their addresses, we could add the address_country, address_city, and address_street to the users table. However, as the database grows, it might make sense to split the users table if we can group specific columns together. To do that, we need to use a one-to-one relationship.
When creating a one-to-one relationship, each row in the first table corresponds to exactly one row in the second table, and vice versa.
In our schema, the address is optional. When we have a one-to-one relationship that is optional we might also refer to it as one-to-zero-or-one relationship.
Creating a migration with the one-to-one relationship
To define a relationship, we need to define a foreign key. It is a column that references another table. A good example is the address_id column, which contains an id of a particular address that belongs to a certain user.
database-schema.ts
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import { serial, text, integer, pgTable } from 'drizzle-orm/pg-core'; export const articles = pgTable('articles', { id: serial('id').primaryKey(), title: text('title'), content: text('content'), }); export const addresses = pgTable('addresses', { id: serial('id').primaryKey(), street: text('street'), city: text('city'), country: text('country'), }); 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 databaseSchema = { articles, addresses, users, }; |
What’s important is that we add a unique constraint to the address_id column. Thanks to that, we ensure that only one user can refer to a particular address. Attaching more than one user to the same address would result in an error.
To create a migration using the Drizzle Kit, we need to run the appropriate command.
1 |
npx drizzle-kit generate --name create-users-and-addresses-tables |
If you want to know more about migrations with Drizzle, check out API with NestJS #149. Introduction to the Drizzle ORM with PostgreSQL
We can now run our migration to add the tables to our database.
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npx drizzle-kit migrate |
Inserting both entities in a single query
We want to insert both the user and the address into the database simultaneously.
First, we create an address. Then, we create the user and use the ID of the created address as the foreign key. If, for some reason, creating the user fails, we don’t want to leave the unnecessary address in the database. To achieve that, we can use a transaction. The crucial aspect of a transaction is that it either succeeds entirely or completely fails. If creating the user fails, Drizzle will roll back the address from the database.
Transactions are a broader topic and deserve a separate article.
users.service.ts
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import { Injectable } from '@nestjs/common'; import { UserDto } from './user.dto'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { isRecord } from '../utilities/isRecord'; import { PostgresErrorCode } from '../database/postgres-error-code.enum'; import { UserAlreadyExistsException } from './user-already-exists.exception'; @Injectable() export class UsersService { constructor(private readonly drizzleService: DrizzleService) {} // ... async createWithAddress(user: UserDto) { return this.drizzleService.db.transaction(async (transaction) => { const createdAddresses = await transaction .insert(databaseSchema.addresses) .values(user.address) .returning(); const createdAddress = createdAddresses.pop(); try { const createdUsers = await transaction .insert(databaseSchema.users) .values({ name: user.name, email: user.email, password: user.password, addressId: createdAddress.id, }) .returning(); return createdUsers.pop(); } catch (error) { if ( isRecord(error) && error.code === PostgresErrorCode.UniqueViolation ) { throw new UserAlreadyExistsException(user.email); } throw error; } }); } } |
Above, we catch the error and compare it to an enum that contains known PostgreSQL error codes.
postgres-error-code.service.ts
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export enum PostgresErrorCode { UniqueViolation = '23505', } |
If the error matches, we throw our custom UserAlreadyExistsException.
user-already-exists.exception.ts
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import { BadRequestException } from '@nestjs/common'; export class UserAlreadyExistsException extends BadRequestException { constructor(email: string) { super(`User with ${email} email already exists`); } } |
Fetching the data from two tables
Our queries can retrieve rows from several tables simultaneously and combine them. One effective method to achieve this is by using a join query.
The most basic type of join is the inner join. The key point is that it only returns records with matching values in both tables. In situations where the address is optional, like in our scenario, executing the query for a user without an address would yield no results.
To resolve the problem, we should use an outer join. Outer joins keep the rows that don’t have corresponding values. Specifically, we should apply a left join, which retrieves all records from the left table along with the matching records from the right table. For us, the left table is users, and the right table is addresses.
users.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 UsersService { constructor(private readonly drizzleService: DrizzleService) {} async getByEmail(email: string) { const allResults = await this.drizzleService.db .select() .from(databaseSchema.users) .where(eq(databaseSchema.users.email, email)) .leftJoin( databaseSchema.addresses, eq(databaseSchema.users.addressId, databaseSchema.addresses.id), ); const result = allResults.pop(); if (!result) { throw new NotFoundException(); } return { ...result.users, address: result.addresses, }; } // ... } |
With this approach, our query successfully handles users who don’t have an address.
Using the Query API
Alternatively, we can use the Query API built into Drizzle to avoid manually dealing with joins. To do that, we first need to define the relationship explicitly in our database schema.
database-schema.ts
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import { serial, text, integer, pgTable } from 'drizzle-orm/pg-core'; import { relations } from 'drizzle-orm'; // ... export const addresses = pgTable('addresses', { id: serial('id').primaryKey(), street: text('street'), city: text('city'), country: text('country'), }); 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 usersAddressesRelation = relations(users, ({ one }) => ({ address: one(addresses, { fields: [users.addressId], references: [addresses.id], }), })); export const databaseSchema = { articles, addresses, users, usersAddressesRelation, }; |
Above, we call the relations() function and export the usersAddressesRelation variable. Now, Drizzle has more information about our relationship and can implicitly perform the joins for us.
users.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 UsersService { constructor(private readonly drizzleService: DrizzleService) {} async getByEmail(email: string) { const user = await this.drizzleService.db.query.users.findFirst({ with: { address: true, }, where: eq(databaseSchema.users.email, email), }); if (!user) { throw new NotFoundException(); } return user; } // ... } |
By using the query.users.findFirst function, we can tell Drizzle which relationships we want to include in our query.
Summary
In this article, we’ve explained the one-to-one relationship and how to implement it with Drizzle. We’ve also learned how to create multiple entities in a single query and how to combine data from two different tables. We’ve done that both by doing joins manually and through the Query API, which simplifies our code.
There is still more to learn about the Drizzle ORM, so stay tuned!
Nice article. Thanks! Tell me please would it be a wrong strategy to not have address_id in User table, to have just user_id as a primary key for addresses and join it by that user_id which is unique and which is used as primary key for Address table? Are there any pitfalls which I don’t see?