Migration Manager

[billy1624]

Hey @oscartbeaumont, thank you for developing the migration tool. We also have a plan for it, see below for details.

• Schema Manager SeaQL/sea-schema#12

[oscartbeaumont]

General:

• Macro to automatically implement MigrationName trait
• Ability to upgrade/downgrade -> Currently Migrator::run only upgrades to the latest version
• Store timestamp of when the migration was run into _sea_migrations table
• Error handling if migration fails -> Add entry to _sea_migrations table but mark it as failed.
• Currently, if you remove a column from a table it must remain in the Rust Model struct for the entire lifetime of the application. Investigate a solution to remove this requirement as it will make the structs of large applications very messy.
• Implement automatic detection of migrations (using Macro?) -> Currently all migrations have to provided in a vector to Migrator::run
• Remove usage of unsafe!!!! (waiting on seaQL/sea-query#183)
• Unit tests
• Convert example to use Backery Schema -> I'm sure this will just make life easier
• Run Tests + Linting in GitHub Actions
• Dependabot

create_table automatic migration support for:

• 1 to many relationship
• many to many relations relationship
• indexed columns

Waiting on seaQL/sea-query#184 so that relations can be automatically created with the add_column helper.

Implement Helpers on MigrationManager:

• rename_column
• has_table
• has_column
• index helpers
• foreign key helpers

Other Issues:

• add_column helper doesn't have if_not_exists and hence will error if executed multiple times.
• Rust doc tests are failing because Sqlite not support dropping table column

Documentation:

• Migrator::run Rust Doc example should contain a migration that is passed to the run function -> Import Bakery Schema?>

Extra Stuff:

• Allow specifying the length of column (Eg. x chars)
• Rust boolean being stored as integer in DB #2

Long Term:

• Detect if already applied migration was changed and throw warning/error -> Use hash stored in _sea_migrations table.

[tyt2y3]

Thank you for such a throughout plan!

I am not aware we still lack several things from SeaQuery

I think Billy & I can start developing sea-query and sea-schema and exposes the class SchemaManager, so MigrationManager can simply wrap or re-export the functionality.

[oscartbeaumont]

I have redone the migration syntax to be more like your example and although I wasn't sure about the syntax at first, I am happy with it now.
It would be great to chat at some point on Discord or whatever about the project and how it integrates into the ecosystem your creating.

[billy1624]

Hey @oscartbeaumont, I have drafted the API of the schema manager on SeaQL/sea-schema#26.

Components

• SchemaManager: Helper struct for writing migration scripts in migration file
• MigrationTrait: Defining the migration
• MigratorTrait: Performing migrations on a database

User can define the migration like this.

• Sample migration
• Migrator
• Main method for running the migrations

It's just a rough POC, please let me know you thought!
I will focus on SchemaManager & MigrationTrait now and will leave MigratorTrait for later.

We could develop it together if you're interested :P

CC @tyt2y3