Prisma Entity Relationship Diagram Generator
Prisma generator to create an ER Diagram every time you generate your prisma client.
Like this tool? @Skn0tt started this effort with his web app ER diagram generator
npm i -D prisma-erd-generator @mermaid-js/mermaid-cli
# or
yarn add -D prisma-erd-generator @mermaid-js/mermaid-cliAdd to your schema.prisma
generator erd {
provider = "prisma-erd-generator"
}Run the generator
npx prisma generate
Versions
- Prisma >= 4 use 1.x.x
- Prisma <4 use 0.11.x
Options
Additional configuration
Output
Change output type and location
Usage
generator erd {
provider = "prisma-erd-generator"
output = "../ERD.svg"
}Extensions
- svg (default:
./prisma/ERD.svg) - png
- md
Theme
Theme selection
Usage
generator erd {
provider = "prisma-erd-generator"
theme = "forest"
}Options
- default (default)
- forest
- dark
- neutral
This option does not accept environment variables or other dynamic values. If you want to change the theme dynamically, you can use the theme option in the mermaidConfig option. See Mermaid Configuration for more information.
mmdcPath
In order for this generator to succeed you must have mmdc installed. This is the mermaid cli tool that is used to generate the ERD. By default the generator searches for an existing binary file at /node_modules/.bin. If it fails to find that binary it will run find ../.. -name mmdc to search through your folder for a mmdc binary. If you are using a different package manager or have a different location for your binary files, you can specify the path to the binary file.
generator erd {
provider = "prisma-erd-generator"
theme = "forest"
mmdcPath = "node_modules/.bin"
}Use with yarn 3+
Yarn 3+ doesn't create a node_modules/.bin directory for scripts when using the pnp or pnpm nodeLinkers (see yarn documentation here). It instead makes scripts available directly from the package.json file using yarn <script_name>, which means that there won't be an mmdc file created at all. This issue can be solved by creating your own shell script named mmdc inside your project's files that runs yarn mmdc (note: this shell script does not need to be added to your package.json file's scripts section - prisma-erd-generatr will access this script directly).
An example mmdc script:
#!/bin/bash
# $@ passes the parameters that this mmdc script was run with along to the mermaid cli
yarn mmdc $@
Make this mmdc script executable by using the command chmod +x mmdc, then set the mmdcPath option to point to the directory where the mmdc file you've just created is stored.
Disabled
You won't always need to generate a new ERD. For instance, when you are building your docker containers you often run prisma generate and if this generator is included, odds are you aren't relying on an updated ERD inside your docker container. It also adds additional space to the container because of dependencies such as puppeteer. There are two ways to disable this ERD generator.
- Via environment variable
DISABLE_ERD=true- Via configuration
generator erd {
provider = "prisma-erd-generator"
disabled = true
}Another option used is to remove the generator lines from your schema before installing dependencies and running the prisma generate command. I have used sed to remove the lines the generator is located on in my schema.prisma file to do so. Here is an example of the ERD generator being removed on lines 5-9 in a dockerfile.
# remove and replace unnecessary generators (erd generator)
# Deletes lines 5-9 from prisma/schema.prisma
RUN sed -i '5,9d' prisma/schema.prismaDebugging
If you have issues with generating or outputting an ERD as expected, you may benefit from seeing output of the steps to making your ERD. Enable debugging by either adding the following environment variable
ERD_DEBUG=trueor adding in the debug configuration key set to true
generator erd {
provider = "prisma-erd-generator"
erdDebug = true
}and re-running prisma generate. You should see a directory and files created labeling the steps to create an ER diagram under prisma/debug.
Please use these files as part of opening an issue if you run into problems.
Table only mode
Table mode only draws your models and skips the attributes and columns associated with your table. This feature is helpful for when you have lots of table columns and they are less helpful than seeing the tables and their relationships
generator erd {
provider = "prisma-erd-generator"
tableOnly = true
}Ignore enums
If you enable this option, enum entities will be hidden. This is useful if you want to reduce the number of entities and focus on the tables and their columns and relationships.
generator erd {
provider = "prisma-erd-generator"
ignoreEnums = true
}Include relation from field
By default this module skips relation fields in the result diagram. For example fields userId and productId will not be generated from this prisma schema.
model User {
id String @id
email String
favoriteProducts FavoriteProducts[]
}
model Product {
id String @id
title String
inFavorites FavoriteProducts[]
}
model FavoriteProducts {
userId String
user User @relation(fields: [userId], references: [id])
productId String
product Product @relation(fields: [productId], references: [id])
@@id([userId, productId])
}
It can be useful to show them when working with RDBMS. To show them use includeRelationFromFields = true
generator erd {
provider = "prisma-erd-generator"
includeRelationFromFields = true
}Disable emoji output
The emoji output for primary keys (🗝️) and nullable fields (❓) can be disabled, restoring the older values of PK and nullable, respectively.
generator erd {
provider = "prisma-erd-generator"
disableEmoji = true
}Mermaid configuration
Overriding the default mermaid configuration may be necessary to represent your schema in the best way possible. There is an example mermaid config here that you can use as a starting point. In the example JavaScript file, types are referenced to view all available options. You can also view them here. The most common use cases for needing to overwrite mermaid configuration is for theming and default sizing of the ERD.
generator erd {
provider = "prisma-erd-generator"
mermaidConfig = "mermaidConfig.json"
}Puppeteer configuration
If you want to change the configuration of Puppeteer, create a Puppeteer config file (JSON) and pass the file path to the generator.
generator erd {
provider = "prisma-erd-generator"
puppeteerConfig = "../puppeteerConfig.json"
}Issues
Because this package relies on mermaid js and puppeteer issues often are opened that relate to those libraries causing issues between different versions of Node.js and your operating system. As a fallback, if you are one of those people not able to generate an ERD using this generator, try running the generator to output a markdown file .md first. Trying to generate a markdown file doesn't run into puppeteer to represent the contents of a mermaid drawing in a browser and often will succeed. This will help get you a functioning ERD while troubleshooting why puppeteer is not working for your machine. Please open an issue if you have any problems or suggestions.
🔴 ARM64 Users 🔴
Puppeteer does not yet come shipped with a version of Chromium for arm64, so you will need to point to a Chromium executable on your system. More details on this issue can be found here.
MacOS Fix:
Install Chromium using Brew:
brew install --cask --no-quarantine chromiumYou should now see the path to your installed Chromium.
which chromiumThe generator will use this Chromium instead of the one provided by Puppeteer.
Other Operating Systems:
This can be fixed by either:
- Setting the
executablePathproperty in your puppeteer config file to the file path of the Chromium executable on your system. - Setting the following global variables on your system
PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true PUPPETEER_EXECUTABLE_PATH=path_to_your_chromium
Contributors ✨
Thanks goes to these wonderful people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome!