Migrate from TypeORM
This guide describes how to migrate from TypeORM to Prisma. It uses an extended version of the TypeORM Express example as a sample project to demonstrate the migration steps. You can find the example used for this guide on GitHub.
This migration guide uses PostgreSQL as the example database, but it equally applies to any other relational database that's supported by Prisma.
You can learn how Prisma compares to TypeORM on the Prisma vs TypeORM page.
Overview of the migration process
Note that the steps for migrating from TypeORM to Prisma are always the same, no matter what kind of application or API layer you're building:
- Install the Prisma CLI
- Introspect your database
- Create a baseline migration
- Install Prisma Client
- Gradually replace your TypeORM queries with Prisma Client
These steps apply, no matter if you're building a REST API (e.g. with Express, koa or NestJS), a GraphQL API (e.g. with Apollo Server, TypeGraphQL or Nexus) or any other kind of application that uses TypeORM for database access.
Prisma lends itself really well for incremental adoption. This means, you don't have migrate your entire project from TypeORM to Prisma at once, but rather you can step-by-step move your database queries from TypeORM to Prisma.
Overview of the sample project
For this guide, we'll use a REST API built with Express as a sample project to migrate to Prisma. It has four models/entities:
@Entity()export class User {@PrimaryGeneratedColumn()id: number@Column({ nullable: true })name: string@Column({ unique: true })email: string@OneToMany((type) => Post, (post) => post.author)posts: Post[]@OneToOne((type) => Profile, (profile) => profile.user, { cascade: true })profile: Profile}
The models have the following relations:
- 1-1:
User
↔Profile
- 1-n:
User
↔Post
- m-n:
Post
↔Category
The corresponding tables have been created using a generated TypeORM migration.
The migration has been created using
$typeorm migration:generate -n Init
This created the following migration file:
migrations/1605698662257-Init.ts
1import { MigrationInterface, QueryRunner } from 'typeorm'23export class Init1605698662257 implements MigrationInterface {4 name = 'Init1605698662257'56 public async up(queryRunner: QueryRunner): Promise<void> {7 await queryRunner.query(8 `CREATE TABLE "profile" ("id" SERIAL NOT NULL, "bio" character varying, "userId" integer, CONSTRAINT "REL_a24972ebd73b106250713dcddd" UNIQUE ("userId"), CONSTRAINT "PK_3dd8bfc97e4a77c70971591bdcb" PRIMARY KEY ("id"))`9 )10 await queryRunner.query(11 `CREATE TABLE "user" ("id" SERIAL NOT NULL, "name" character varying, "email" character varying NOT NULL, CONSTRAINT "UQ_e12875dfb3b1d92d7d7c5377e22" UNIQUE ("email"), CONSTRAINT "PK_cace4a159ff9f2512dd42373760" PRIMARY KEY ("id"))`12 )13 await queryRunner.query(14 `CREATE TABLE "post" ("id" SERIAL NOT NULL, "title" character varying NOT NULL, "content" character varying, "published" boolean NOT NULL DEFAULT false, "authorId" integer, CONSTRAINT "PK_be5fda3aac270b134ff9c21cdee" PRIMARY KEY ("id"))`15 )16 await queryRunner.query(17 `CREATE TABLE "category" ("id" SERIAL NOT NULL, "name" character varying NOT NULL, CONSTRAINT "PK_9c4e4a89e3674fc9f382d733f03" PRIMARY KEY ("id"))`18 )19 await queryRunner.query(20 `CREATE TABLE "post_categories_category" ("postId" integer NOT NULL, "categoryId" integer NOT NULL, CONSTRAINT "PK_91306c0021c4901c1825ef097ce" PRIMARY KEY ("postId", "categoryId"))`21 )22 await queryRunner.query(23 `CREATE INDEX "IDX_93b566d522b73cb8bc46f7405b" ON "post_categories_category" ("postId") `24 )25 await queryRunner.query(26 `CREATE INDEX "IDX_a5e63f80ca58e7296d5864bd2d" ON "post_categories_category" ("categoryId") `27 )28 await queryRunner.query(29 `ALTER TABLE "profile" ADD CONSTRAINT "FK_a24972ebd73b106250713dcddd9" FOREIGN KEY ("userId") REFERENCES "user"("id") ON DELETE NO ACTION ON UPDATE NO ACTION`30 )31 await queryRunner.query(32 `ALTER TABLE "post" ADD CONSTRAINT "FK_c6fb082a3114f35d0cc27c518e0" FOREIGN KEY ("authorId") REFERENCES "user"("id") ON DELETE NO ACTION ON UPDATE NO ACTION`33 )34 await queryRunner.query(35 `ALTER TABLE "post_categories_category" ADD CONSTRAINT "FK_93b566d522b73cb8bc46f7405bd" FOREIGN KEY ("postId") REFERENCES "post"("id") ON DELETE CASCADE ON UPDATE NO ACTION`36 )37 await queryRunner.query(38 `ALTER TABLE "post_categories_category" ADD CONSTRAINT "FK_a5e63f80ca58e7296d5864bd2d3" FOREIGN KEY ("categoryId") REFERENCES "category"("id") ON DELETE CASCADE ON UPDATE NO ACTION`39 )40 }4142 public async down(queryRunner: QueryRunner): Promise<void> {43 await queryRunner.query(44 `ALTER TABLE "post_categories_category" DROP CONSTRAINT "FK_a5e63f80ca58e7296d5864bd2d3"`45 )46 await queryRunner.query(47 `ALTER TABLE "post_categories_category" DROP CONSTRAINT "FK_93b566d522b73cb8bc46f7405bd"`48 )49 await queryRunner.query(50 `ALTER TABLE "post" DROP CONSTRAINT "FK_c6fb082a3114f35d0cc27c518e0"`51 )52 await queryRunner.query(53 `ALTER TABLE "profile" DROP CONSTRAINT "FK_a24972ebd73b106250713dcddd9"`54 )55 await queryRunner.query(`DROP INDEX "IDX_a5e63f80ca58e7296d5864bd2d"`)56 await queryRunner.query(`DROP INDEX "IDX_93b566d522b73cb8bc46f7405b"`)57 await queryRunner.query(`DROP TABLE "post_categories_category"`)58 await queryRunner.query(`DROP TABLE "category"`)59 await queryRunner.query(`DROP TABLE "post"`)60 await queryRunner.query(`DROP TABLE "user"`)61 await queryRunner.query(`DROP TABLE "profile"`)62 }63}
As mentioned before, this guide is an extended variation of the TypeORM Express example and uses the same file structure. The route handlers are located in the src/controller
directory. From there, they are pulled into a central src/routes.ts
file which is used to set up the required routes in src/index.ts
:
└── blog-typeorm├── ormconfig.json├── package.json├── src│ ├── controllers│ │ ├── AddPostToCategoryAction.ts│ │ ├── CreateDraftAction.ts│ │ ├── CreateUserAction.ts│ │ ├── FeedAction.ts│ │ ├── FilterPostsAction.ts│ │ ├── GetPostByIdAction.ts│ │ └── SetBioForUserAction.ts│ ├── entity│ │ ├── Category.ts│ │ ├── Post.ts│ │ ├── Profile.ts│ │ └── User.ts│ ├── index.ts│ ├── migration│ │ └── 1605698662257-Init.ts│ └── routes.ts└── tsconfig.json
Step 1. Install the Prisma CLI
The first step to adopt Prisma is to install the Prisma CLI in your project:
$
Step 2. Introspect your database
2.1. Set up Prisma
Before you can introspect your database, you need to set up your Prisma schema and connect Prisma to your database. Run the following command in your terminal to create a basic Prisma schema file:
$
This command created a new directory called prisma
with the following files for you:
schema.prisma
: Your Prisma schema file that specifies your database connection and models.env
: Adotenv
to configure your database connection URL as an environment variable
The Prisma schema file currently looks as follows:
prisma/schema.prisma
1// This is your Prisma schema file,2// learn more about it in the docs: https://pris.ly/d/prisma-schema34datasource db {5 provider = "postgresql"6 url = env("DATABASE_URL")7}89generator client {10 provider = "prisma-client-js"11}
If you're using VS Code, be sure to install the Prisma VS Code extension for syntax highlighting, formatting, auto-completion and a lot more cool features.
2.2. Connect your database
If you're not using PostgreSQL, you need to adjust the provider
field on the datasource
block to the database you currently use:
schema.prisma
1datasource db {2 provider = "postgresql"3 url = env("DATABASE_URL")4}
Once that's done, you can configure your database connection URL in the .env
file. Here's how the database connection from TypeORM maps to the connection URL format used by Prisma:
Assume you have the following database connection details in ormconfig.json
:
ormconfig.json
1{2 "type": "postgres",3 "host": "localhost",4 "port": 5432,5 "username": "alice",6 "password": "myPassword42",7 "database": "blog-typeorm"8}
The respective connection URL would look as follows in Prisma:
.env
1DATABASE_URL="postgresql://alice:myPassword42@localhost:5432/blog-typeorm"
Note that you can optionally configure the PostgreSQL schema by appending the schema
argument to the connection URL:
.env
1DATABASE_URL="postgresql://alice:myPassword42@localhost:5432/blog-typeorm?schema=myschema"
If not provided, the default schema called public
is being used.
2.3. Introspect your database using Prisma
With your connection URL in place, you can introspect your database to generate your Prisma models:
$
This creates the following Prisma models:
prisma/schema.prisma
1model typeorm_migrations {2 id Int @id @default(autoincrement())3 timestamp Int4 name String56 @@map("_typeorm_migrations")7}89model category {10 id Int @id @default(autoincrement())11 name String12 post_categories_category post_categories_category[]13}1415model post {16 id Int @id @default(autoincrement())17 title String18 content String?19 published Boolean @default(false)20 authorId Int?21 user user? @relation(fields: [authorId], references: [id])22 post_categories_category post_categories_category[]23}2425model post_categories_category {26 postId Int27 categoryId Int28 category category @relation(fields: [categoryId], references: [id])29 post post @relation(fields: [postId], references: [id])3031 @@id([postId, categoryId])32 @@index([postId], name: "IDX_93b566d522b73cb8bc46f7405b")33 @@index([categoryId], name: "IDX_a5e63f80ca58e7296d5864bd2d")34}3536model profile {37 id Int @id @default(autoincrement())38 bio String?39 userId Int? @unique40 user user? @relation(fields: [userId], references: [id])41}4243model user {44 id Int @id @default(autoincrement())45 name String?46 email String @unique47 post post[]48 profile profile?49}
The generated Prisma models represent your database tables and are the foundation for your programmatic Prisma Client API which allows you to send queries to your database.
2.4. Create a baseline migration
To continue using Prisma Migrate to evolve your database schema, you will need to baseline your database.
First, create a migrations
directory and add a directory inside with your preferred name for the migration. In this example, we will use 0_init
as the migration name:
$mkdir -p prisma/migrations/0_init
Next, generate the migration file with prisma migrate diff
. Use the following arguments:
--from-empty
: assumes the data model you're migrating from is empty--to-schema-datamodel
: the current database state using the URL in thedatasource
block--script
: output a SQL script
$npx prisma migrate diff --from-empty --to-schema-datamodel prisma/schema.prisma --script > prisma/migrations/0_init/migration.sql
Review the generated migration to ensure everything is correct.
Next, mark the migration as applied using prisma migrate resolve
with the --applied
argument.
$npx prisma migrate resolve --applied 0_init
The command will mark 0_init
as applied by adding it to the _prisma_migrations
table.
You now have a baseline for your current database schema. To make further changes to your database schema, you can update your Prisma schema and use prisma migrate dev
to apply the changes to your database.
2.5. Adjust the Prisma schema (optional)
The models that were generated via introspection currently exactly map to your database tables. In this section, you'll learn how you can adjust the naming of the Prisma models to adhere to Prisma's naming conventions.
All of these adjustment are entirely optional and you are free to skip to the next step already if you don't want to adjust anything for now. You can go back and make the adjustments at any later point.
As opposed to the current snake_case notation of TypeORM models, Prisma's naming conventions are:
- PascalCase for model names
- camelCase for field names
You can adjust the naming by mapping the Prisma model and field names to the existing table and column names in the underlying database using @@map
and @map
.
Also note that you can rename relation fields to optimize the Prisma Client API that you'll use later to send queries to your database. For example, the post
field on the user
model is a list, so a better name for this field would be posts
to indicate that it's plural.
You can further completely remove model that represents the TypeORM migrations table (called _typeorm_migrations
here) from the Prisma schema.
Here's an adjusted version of the Prisma schema that addresses these points:
prisma/schema.prisma
1model Category {2 id Int @id @default(autoincrement())3 name String4 postsToCategories PostToCategories[]56 @@map("category")7}89model Post {10 id Int @id @default(autoincrement())11 title String12 content String?13 published Boolean @default(false)14 authorId Int?15 author User? @relation(fields: [authorId], references: [id])16 postsToCategories PostToCategories[]1718 @@map("post")19}2021model PostToCategories {22 postId Int23 categoryId Int24 category Category @relation(fields: [categoryId], references: [id])25 post Post @relation(fields: [postId], references: [id])2627 @@id([postId, categoryId])28 @@index([postId], name: "IDX_93b566d522b73cb8bc46f7405b")29 @@index([categoryId], name: "IDX_a5e63f80ca58e7296d5864bd2d")30 @@map("post_categories_category")31}3233model Profile {34 id Int @id @default(autoincrement())35 bio String?36 userId Int? @unique37 user User? @relation(fields: [userId], references: [id])3839 @@map("profile")40}4142model User {43 id Int @id @default(autoincrement())44 name String?45 email String @unique46 posts Post[]47 profile Profile?4849 @@map("user")50}
Step 3. Install Prisma Client
As a next step, you can install Prisma Client in your project so that you can start replacing the database queries in your project that are currently made with TypeORM:
$npm install @prisma/client
Step 4. Replace your TypeORM queries with Prisma Client
In this section, we'll show a few sample queries that are being migrated from TypeORM to Prisma Client based on the example routes from the sample REST API project. For a comprehensive overview of how the Prisma Client API differs from TypeORM, check out the API comparison page.
First, to set up the PrismaClient
instance that you'll use to send database queries from the various route handlers. Create a new file named prisma.ts
in the src
directory:
$
Now, instantiate PrismaClient
and export it from the file so you can use it in your route handlers later:
src/prisma.ts
123
4.1. Replacing queries in GET
requests
The REST API has three routes that accept GET
requests:
/feed
: Return all published posts/filterPosts?searchString=SEARCH_STRING
: Filter returned posts bySEARCH_STRING
/post/:postId
: Returns a specific post
Let's dive into the route handlers that implement these requests.
/feed
The /feed
handler is currently implemented as follows:
src/controllers/FeedAction.ts
1import { getManager } from 'typeorm'2import { Post } from '../entity/Post'34export async function feedAction(req, res) {5 const postRepository = getManager().getRepository(Post)67 const publishedPosts = await postRepository.find({8 where: { published: true },9 relations: ['author'],10 })1112 res.send(publishedPosts)13}
Note that each returned Post
object includes the relation to the author
it's associated with. With TypeORM, including the relation is not type-safe. For example, if there was a typo in the relation that is retrieved, your database query would fail only at runtime – the TypeScript compiler does not provide any safety here.
Here is how the same route is implemented using Prisma Client:
src/controllers/FeedAction.ts
1import { prisma } from '../prisma'23export async function feedAction(req, res) {4 const publishedPosts = await prisma.post.findMany({5 where: { published: true },6 include: { author: true },7 })89 res.send(publishedPosts)10}
Note that the way how Prisma Client includes the author
relation is absolutely type-safe. The TypeScript compiler would throw an error if you were trying to include a relation that does not exist on the Post
model.
/filterPosts?searchString=SEARCH_STRING
The /filterPosts
handler is currently implemented as follows:
src/controllers/FilterPostsActions.ts
1import { getManager, Like } from 'typeorm'2import { Post } from '../entity/Post'34export async function filterPostsAction(req, res) {5 const { searchString } = req.query6 const postRepository = getManager().getRepository(Post)78 const filteredPosts = await postRepository.find({9 where: [10 { title: Like(`%${searchString}%`) },11 { content: Like(`%${searchString}%`) },12 ],13 })1415 res.send(filteredPosts)16}
With Prisma, the route is implemented as follows:
src/controllers/FilterPostsActions.ts
1import { prisma } from '../prisma'23export async function filterPostsAction(req, res) {4 const { searchString } = req.query56 const filteredPosts = prisma.post.findMany({7 where: {8 OR: [9 {10 title: { contains: searchString },11 },12 {13 content: { contains: searchString },14 },15 ],16 },17 })1819 res.send(filteredPosts)20}
Note that TypeORM by default combines several where
conditions with an implicit OR
operator. Prisma on the other hand combines several where
conditions with an implicit AND
operator, so in this case the Prisma query needs to make the OR
explicit.
/post/:postId
The /post/:postId
handler is currently implemented as follows:
src/controllers/GetPostByIdAction.ts
1import { getManager } from 'typeorm'2import { Post } from '../entity/Post'34export async function getPostByIdAction(req, res) {5 const { postId } = req.params6 const postRepository = getManager().getRepository(Post)78 const post = await postRepository.findOne(postId)910 res.send(post)11}
With Prisma, the route is implemented as follows:
src/controllers/GetPostByIdAction.ts
1import { prisma } from '../prisma'23export async function getPostByIdAction(req, res) {4 const { postId } = req.params56 const post = await prisma.post.findUnique({7 where: { id: postId },8 })910 res.send(post)11}
4.2. Replacing queries in POST
requests
The REST API has three routes that accept POST
requests:
/user
: Creates a newUser
record/post
: Creates a newPost
record/user/:userId/profile
: Creates a newProfile
record for aUser
record with a given ID
/user
The /user
handler is currently implemented as follows:
src/controllers/CreateUserAction.ts
1import { getManager } from 'typeorm'2import { User } from '../entity/User'34export async function createUserAction(req, res) {5 const { name, email } = req.body67 const userRepository = getManager().getRepository(User)89 const newUser = new User()10 newUser.name = name11 newUser.email = email12 userRepository.save(newUser)1314 res.send(newUser)15}
With Prisma, the route is implemented as follows:
src/controllers/CreateUserAction.ts
1import { prisma } from '../prisma'23export async function createUserAction(req, res) {4 const { name, email } = req.body56 const newUser = await prisma.user.create({7 data: {8 name,9 email,10 },11 })1213 res.send(newUser)14}
/post
The /post
handler is currently implemented as follows:
src/controllers/CreateDraftAction.ts
1import { getManager } from 'typeorm'2import { Post } from '../entity/Post'3import { User } from '../entity/User'45export async function createDraftAction(req, res) {6 const { title, content, authorEmail } = req.body78 const userRepository = getManager().getRepository(User)9 const user = await userRepository.findOne({ email: authorEmail })1011 const postRepository = getManager().getRepository(Post)1213 const newPost = new Post()14 newPost.title = title15 newPost.content = content16 newPost.author = user17 postRepository.save(newPost)1819 res.send(newPost)20}
With Prisma, the route is implemented as follows:
src/controllers/CreateDraftAction.ts
1import { prisma } from '../prisma'23export async function createDraftAction(req, res) {4 const { title, content, authorEmail } = req.body56 const newPost = await prisma.post.create({7 data: {8 title,9 content,10 author: {11 connect: { email: authorEmail },12 },13 },14 })1516 res.send(newPost)17}
Note that Prisma Client's nested write here save an initial query where first the User
record needs to be retrieved by its email
. That's because, with Prisma you can connect records in relations using any unique property.
/user/:userId/profile
The /user/:userId/profile
handler is currently implemented as follows:
src/controllers/SetBioForUserAction.ts.ts
1import { getManager } from 'typeorm'2import { Profile } from '../entity/Profile'3import { User } from '../entity/User'45export async function setBioForUserAction(req, res) {6 const { userId } = req.params7 const { bio } = req.body89 const userRepository = getManager().getRepository(User)10 const user = await userRepository.findOne(userId, {11 relations: ['profile'],12 })1314 const profileRepository = getManager().getRepository(Profile)15 user.profile.bio = bio1617 profileRepository.save(user.profile)1819 res.send(user)20}
With Prisma, the route is implemented as follows:
src/controllers/SetBioForUserAction.ts.ts
1import { prisma } from '../prisma'23export async function setBioForUserAction(req, res) {4 const { userId } = req.params5 const { bio } = req.body67 const user = await prisma.user.update({8 where: { id: userId },9 data: {10 profile: {11 update: {12 bio,13 },14 },15 },16 })1718 res.send(user)19}
4.3. Replacing queries in PUT
requests
The REST API has one route that accept a PUT
request:
/addPostToCategory?postId=POST_ID&categoryId=CATEGORY_ID
: Adds the post withPOST_ID
to the category withCATEGORY_ID
Let's dive into the route handlers that implement these requests.
/addPostToCategory?postId=POST_ID&categoryId=CATEGORY_ID
The /addPostToCategory?postId=POST_ID&categoryId=CATEGORY_ID
handler is currently implemented as follows:
src/controllers/AddPostToCategoryAction.ts
1import { getManager } from 'typeorm'2import { Post } from '../entity/Post'3import { Category } from '../entity/Category'45export async function addPostToCategoryAction(req, res) {6 const { postId, categoryId } = req.query78 const postRepository = getManager().getRepository(Post)9 const post = await postRepository.findOne(postId, {10 relations: ['categories'],11 })1213 const categoryRepository = getManager().getRepository(Category)14 const category = await categoryRepository.findOne(categoryId)1516 post.categories.push(category)17 postRepository.save(post)1819 res.send(post)20}
With Prisma, the route is implemented as follows:
src/controllers/AddPostToCategoryAction.ts
1import { prisma } from '../prisma'23export async function addPostToCategoryAction(req, res) {4 const { postId, categoryId } = req.query56 const post = await prisma.post.update({7 data: {8 postsToCategories: {9 create: {10 category: {11 connect: { id: categoryId },12 },13 },14 },15 },16 where: {17 id: postId,18 },19 })2021 res.send(post)22}
Note that this Prisma Client can be made less verbose by modeling the relation as an implicit many-to-many relation instead. In that case, the query would look as follows:
src/controllers/AddPostToCategoryAction.ts
1const post = await prisma.post.update({2 data: {3 categories: {4 connect: { id: categoryId },5 },6 },7 where: { id: postId },8})
More
Implicit many-to-many relations
Similar to the @manyToMany
decorator in TypeORM, Prisma allows you to model many-to-many relations implicitly. That is, a many-to-many relation where you do not have to manage the relation table (also sometimes called JOIN table) explicitly in your schema. Here is an example with TypeORM:
import {Entity,PrimaryGeneratedColumn,Column,ManyToMany,JoinTable,} from 'typeorm'import { Category } from './Category'@Entity()export class Post {@PrimaryGeneratedColumn()id: number@ManyToMany((type) => Category, (category) => category.posts)@JoinTable()categories: Category[]}
import { Entity, PrimaryGeneratedColumn, Column, ManyToMany } from 'typeorm'import { Post } from './Post'@Entity()export class Category {@PrimaryGeneratedColumn()id: number@ManyToMany((type) => Post, (post) => post.categories)posts: Post[]}
If you generate and run a migration with TypeORM based on these models, TypeORM will automatically create the following relation table for you:
-- Table Definition ----------------------------------------------CREATE TABLE post_categories_category ("postId" integer REFERENCES post(id) ON DELETE CASCADE,"categoryId" integer REFERENCES category(id) ON DELETE CASCADE,CONSTRAINT "PK_91306c0021c4901c1825ef097ce" PRIMARY KEY ("postId", "categoryId"));-- Indices -------------------------------------------------------CREATE UNIQUE INDEX "PK_91306c0021c4901c1825ef097ce" ON post_categories_category("postId" int4_ops,"categoryId" int4_ops);CREATE INDEX "IDX_93b566d522b73cb8bc46f7405b" ON post_categories_category("postId" int4_ops);CREATE INDEX "IDX_a5e63f80ca58e7296d5864bd2d" ON post_categories_category("categoryId" int4_ops);
If you introspect the database with Prisma, you'll get the following result in the Prisma schema (note that some relation field names have been adjusted to look friendlier compared to the raw version from introspection):
schema.prisma
1model Category {2 id Int @id @default(autoincrement())3 name String4 postsToCategories PostToCategories[]56 @@map("category")7}89model Post {10 id Int @id @default(autoincrement())11 title String12 content String?13 published Boolean @default(false)14 authorId Int?15 author User? @relation(fields: [authorId], references: [id])16 postsToCategories PostToCategories[]1718 @@map("post")19}2021model PostToCategories {22 postId Int23 categoryId Int24 category Category @relation(fields: [categoryId], references: [id])25 post Post @relation(fields: [postId], references: [id])2627 @@id([postId, categoryId])28 @@index([postId], name: "IDX_93b566d522b73cb8bc46f7405b")29 @@index([categoryId], name: "IDX_a5e63f80ca58e7296d5864bd2d")30 @@map("post_categories_category")31}
In this Prisma schema, the many-to-many relation is modeled explicitly via the relation table PostToCategories
.
By adhering to the conventions for Prisma relation tables, the relation could look as follows:
schema.prisma
1model Category {2 id Int @id @default(autoincrement())3 name String4 posts Post[]56 @@map("category")7}89model Post {10 id Int @id @default(autoincrement())11 title String12 content String?13 published Boolean @default(false)14 authorId Int?15 author User? @relation(fields: [authorId], references: [id])16 categories Category[]1718 @@map("post")19}
This would also result in a more ergonomic and less verbose Prisma Client API to modify the records in this relation, because you have a direct path from Post
to Category
(and the other way around) instead of needing to traverse the PostToCategories
model first.