- 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
Thanks to some of its features, PostgreSQL sets itself apart from other SQL databases. Unlike many SQL databases that limit columns to single entries, PostgreSQL lets us store multiple values in a single column. This simplifies database design and can improve performance. In this article, we will explore the practical uses of arrays in PostgreSQL and show how to use them with the Drizzle ORM.
The array column
In earlier sections of this series, we created the structure for a table that holds articles.
database-schema.ts
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export const articles = pgTable('articles', { id: serial('id').primaryKey(), title: text('title').notNull(), content: text('content').notNull(), authorId: integer('author_id') .references(() => users.id) .notNull(), }); |
This time, instead of a plain text column for the article’s content, let’s use an array. To do that, we need the array() function.
database-schema.ts
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export const articles = pgTable('articles', { id: serial('id').primaryKey(), title: text('title').notNull(), paragraphs: text('paragraphs').array().notNull(), authorId: integer('author_id') .references(() => users.id) .notNull(), }); // ... |
We can now use the Drizzle ORM Kit to create a migration.
1 |
npx drizzle-kit generate --name change-article-content-to-paragraphs |
Drizzle ORM Kit will ask if you want to rename the content column to paragraphs or create a new column from scratch. We, however, want to do something a bit more advanced since the type of our column changes from a simple string to an array of strings.
To avoid losing the data already stored in the content array, let’s set it as the first element of the paragraphs array and then remove the content column.
0005_change-article-content-to-paragraphs.sql
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ALTER TABLE articles ADD COLUMN paragraphs TEXT[]; UPDATE articles SET paragraphs = ARRAY[content]; ALTER TABLE articles DROP COLUMN content; |
Thanks to this approach, we don’t lose the data stored in our database when we run our migration.
Working with arrays using the Drizzle ORM
It’s very straightforward to insert a record into the table that contains an array.
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await this.drizzleService.db .insert(databaseSchema.articles) .values({ authorId: 1, title: 'My article', paragraphs: [ 'First paragraph', 'Second paragraph' ], }) .returning(); |
To achieve that in a NestJS application, we need to adjust the Data Transfer Objects so that users can send arrays to our REST API.
create-article.dto.ts
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import { IsString, IsNotEmpty, IsOptional, IsNumber } from 'class-validator'; export class CreateArticleDto { @IsString() @IsNotEmpty() content: string; @IsString({ each: true }) @IsNotEmpty({ each: true }) paragraphs: string[]; @IsOptional() @IsNumber({}, { each: true }) categoryIds: number[] = []; } |
Above, we use the class-validator library to ensure that the user provides a valid array of strings.
We can now adjust our service and use the paragraphs property from our DTO.
articles.service.ts
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import { BadRequestException, Injectable } from '@nestjs/common'; import { DrizzleService } from '../database/drizzle.service'; import { databaseSchema } from '../database/database-schema'; import { CreateArticleDto } from './dto/create-article.dto'; import { isDatabaseError } from '../database/databse-error'; import { PostgresErrorCode } from '../database/postgres-error-code.enum'; @Injectable() export class ArticlesService { constructor(private readonly drizzleService: DrizzleService) {} async create(article: CreateArticleDto, authorId: number) { try { const createdArticles = await this.drizzleService.db .insert(databaseSchema.articles) .values({ authorId, title: article.title, paragraphs: article.paragraphs, }) .returning(); return createdArticles.pop(); } catch (error) { if (!isDatabaseError(error)) { throw error; } if (error.code === PostgresErrorCode.NotNullViolation) { throw new BadRequestException( `The value of ${error.column} can not be null`, ); } if (error.code === PostgresErrorCode.CheckViolation) { throw new BadRequestException('The title can not be an empty string'); } throw error; } } // ... } |
Updating existing records
The most straightforward way of modifying an array is to provide a brand-new one, even if we want to change only some elements.
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await this.drizzleService.db .update(databaseSchema.articles) .set({ title: 'My article', paragraphs: [ 'New first paragraph', 'Second paragraph' ], }) .where(eq(databaseSchema.articles.id, id)) .returning(); |
Aside from allowing us to set the entire array’s contents when modifying it, PostgreSQL provides various functions. However, we need to write raw SQL to achieve that.
For example, using array_append, we can add a new element at the end of an existing array.
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await this.drizzleService.db .update(databaseSchema.articles) .set({ title: 'My article', paragraphs: sql`array_append(${databaseSchema.articles.paragraphs}, ${'Final paragraph'})`, }) .where(eq(databaseSchema.articles.id, id)) .returning(); |
The sql tagged template is imported from the drizzle-orm library. If you want to know more about tagged templates, check out Concatenating strings with template literals. Tagged templates
Similarly, the array_prepend function adds an element to the beginning of the array.
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await this.drizzleService.db .update(databaseSchema.articles) .set({ title: 'My article', paragraphs: sql`array_prepend(${databaseSchema.articles.paragraphs}, ${'Initial paragraph'})`, }) .where(eq(databaseSchema.articles.id, id)) .returning(); |
With the trim_array function, we can remove a particular number of elements from the end of an array. For example, let’s use it to delete the last element.
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await this.drizzleService.db .update(databaseSchema.articles) .set({ title: 'My article', paragraphs: sql`trim_array(${databaseSchema.articles.paragraphs}, 1)`, }) .where(eq(databaseSchema.articles.id, id)) .returning(); |
Searching through arrays
With PostgreSQL, we can search through arrays with the ALL and ANY operators.
For example, we can find articles where all paragraphs equal a particular string using the ALL keyword.
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this.drizzleService.db .select() .from(databaseSchema.articles) .where( sql` ${'Lorem ipsum'} = ALL(${databaseSchema.articles.paragraphs}) `, ); |
What might be more practical is that we can use the ANY operator to get the articles where any paragraph equals a particular string.
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this.drizzleService.db .select() .from(databaseSchema.articles) .where( sql` ${'Lorem ipsum'} = ANY(${databaseSchema.articles.paragraphs}) `, ); |
In addition to the above, we can use the array_length function to filter the records based on the number of elements in the array. For example, we can find all articles with at least one paragraph.
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this.drizzleService.db .select() .from(databaseSchema.articles) .where( sql` array_length(${databaseSchema.articles.paragraphs}, 1) > 1 `, ); |
With the second argument of the array_length function we specify which dimension of the array we want to measure. It can be useful for multi-dimensional arrays.
Summary
In this article, we explored the use of array columns and implemented examples using the Drizzle ORM. Array columns can store multiple related values within a single column in PostgreSQL, aided by built-in functions and operators for various tasks. Unfortunately, though, arrays aren’t always the best solution.
Indexing and querying arrays can be inefficient with large datasets. In such cases, creating a separate table and defining relationships might be a better approach, especially if we want to enforce specific data constraints. Evaluating your application’s needs and weighing the advantages and disadvantages before opting for array columns in PostgreSQL is crucial. However, having an extra tool in your toolbox is always beneficial.