Allowing multiple print_schema

[forest1102]

Your project helps a lot.
One feature I want is splitting into multiple schema.rs.
For instance, making the following diesel.toml

[[print_schema]]
file = "db_company/src/schema.rs"
filter = { only_tables = ["^companies$"] }
[[print_schema]]
file = "db_user/src/schema.rs"
filter = { only_tables = ["^users$"] }

Then, the companies schema info is written in db_company/src/schema.rs, while the users schema info goes to db_user/src/schema.rs.

Current Behavior

print_schema field only allows only on schema info.
So, what I do right now is select one print_schema and comment out others like the following files.

[print_schema]
file = "db_company/src/schema.rs"
filter = { only_tables = ["^companies$"] }
# [print_schema]
# file = "db_user/src/schema.rs"
# filter = { only_tables = ["^users$"] }

Motivation

• Readability
  • By splitting schema.rs, we can easily search definition of tables.
• Build Performance
  • This feature will parallelize building schema.rs. which will result in better build performance.

How to do

• make print_schma field in diesel.toml to either single or multiple print_schema
• edit print_schema.rs to run multiple time.

[weiznich]

Thanks for writing this proposal. This feature is essentially a duplicate of #1728. We are happy to accept contributions there, but I personally do not plan to work on this feature soon.

If you start working on this you need to keep in mind that this needs to be implemented in a backward compatible way. It's not clear from your proposal how that would be achieved, as toml does as far as I know not support moving a field from [print_schema] (singular) to [[print_schema]]