Dynamic Table Name， a lot of tables with the same structure, it is not appropriate to define many structures with macros

[langzime]

Motivation

Proposed Solutions

Additional Information

[billy1624]

Hey @langzime, is this a follow up question of

• https://github.com/SeaQL/sea-orm/issues/782

[billy1624]

Yeah, this is the tradeoff. Defining the repeated structs over and over again OR defining repeated struct with macro. Define with macro will improve the readability and avoid repeated code but it's harder to develop upon as not all IDEs are able to expand the macros.

[langzime]

Yes, i tried it. A lot of macros cause ide very laggy and a lot of extra code

[billy1624]

From my experience, it's just a one-time long compilation as 200+ entities were added at once. Once it's compiled it will never be recompiled on the same machine given the fact that entity file is unchanged.

[langzime]

I have 500+ ...

[langzime]

In cases like this, I currently use both mysql_async

[billy1624]

I think there are three options:

1. Fork SeaORM and change this part, making it to be provided in runtime: https://github.com/SeaQL/sea-orm/blob/1ea8b457bf9f66988a45696c15933a6a756854ed/src/tests_cfg/cake_expanded.rs#L7-L11
2. Construct SQL statement with SeaQuery then pass it to SeaORM for execution: https://github.com/SeaQL/starfish-ql/blob/459a71609785f74739d4b5ba9a2983af0cedfae6/starfish/starfish-core/src/query/mod.rs#L290-L303

[langzime]

Thank you very much, I'll try it sometime. Do you have plans to support this feature?

[billy1624]

Do you have plans to support this feature?

It's not on our plan. But if you have an good proposal we're willing to consider :D

[tyt2y3]

Actually, it's possible to have an Entity that has a state, so your Entity is no longer a unit struct, but a struct Entity(String).

[tyt2y3]

Although I am not sure are there other blockers to this approach. But yeah at least it was designed that way, the table_name takes a self

[billy1624]

From table_name perspective, it's designed with runtime in mind. https://github.com/SeaQL/sea-orm/blob/6bc76698cc54aea1eb54cbd82d1d5af096432079/src/entity/base_entity.rs#L23-L24

However, when constructing query. It doesn't take &self. So, it's solely rely on the Entity defined in compile-time.

Also, EntityName must be Copy but String isn't. So, pub struct Entity(pub String) wouldn't compile.

https://github.com/SeaQL/sea-orm/blob/6bc76698cc54aea1eb54cbd82d1d5af096432079/src/entity/base_entity.rs#L10-L24

[tyt2y3]

Then probably a lazy_static with Entity(&'static str) would work