Database Migrations in Dart-land
Overview
If there’s one thing my coworkers would say about me, it’s that I’m a little obsessed with figuring out how to make Dart work on the backend; One of my primary focuses has been on finding a solid ORM with migrations.
Why? For me, there are two main reasons:
Writing the same CRUD operations for every entity is tedious, time-consuming, and error-prone
Schema changes should be tracked in VC and be synchronized with your entity models
After a lot of trial-and-error, I finally felt that there wasn’t an ORM available that really suited me. So, fine, I will write the SQL queries and handle serialization/deserialization myself (with the help of codegen, anyway).
However, that still doesn’t address my desire for a migration system. Pair this with my recent inclination to make the tools I need instead of waiting for someone else to do it and, ta-da: dart_migrator!
It’s still in its early phases and hasn’t been published to pub.dev yet, but the idea is that: I will write the SQL queries and maintain the models, I will even write the migration queries, but dart_migrator will handle running the migrations as needed.
Basic Usage
Installation
Install dart_migrator to your package’s dev dependencies (for now, directly from GitHub)
Creating a migration
Use the dart_migrator CLI to create a new migration:
The “n” flag is required and represents the “name” of your new migration.
The result of this command will be a new folder:
In this folder will be empty up.sql and down.sql files. Write your changes in the up.sql file; write the inverse of these changes in down.sql.
Running migrations
Once you have new migrations, use the CLI tool to run all pending migrations against your database.
The “env” flag signifies that the tool should look for a DATABASE_URL key in a .env file in your root directory. If you don’t have a .env file or would rather pass the URL on the command-line, use the “url” flag.
dart_migrator will look for new migrations, tracked by the migrations table (created and maintained by the CLI tool).
Configuration
The tool can be configured using a dart_migrator.yaml file in the root of your project.
There is still a lot of work to do, but this fills a gap in the Dart ecosystem for me and I hope it helps you, too!
