@weiznich I have a bunch models for which I just need to do simple CRUD operations, so I would like to write trait that defines those methods and then just implement it for my models, something like this:

pub trait Create: Comment {
    fn create(self, pool: DBPool) -> Result<usize, Error> {
        let conn = pool.get()?;
        let result = diesel::insert_into(comments::table)
            .values(self)
            .execute(&conn)?;
        Ok(result)
    }
}

The problem is that I need to write the trait for each different model, while I would like to write it once and reuse it for any model. What should be the trait bounds I should declare so that it works for any Insertable, Changeset or Queryable?

@codearm_gitlab I do not see why you would need a Create trait for each struct? Something like

trait Create {
     fn create(self, pool: DBPool) -> Result<usize, Error>;
}

can easily be implemented for all types you want.
Additionally: Can you explain what code you would reuse exactly?

@weiznich I could do that, but then I would have to write

 let conn = pool.get()?;
 let result = diesel::insert_into(comments::table)
        .values(self)
        .execute(&conn)?;
 Ok(result)

For each one of them, I know, it is not much but it is not very good practice to have duplicated code around

Unexpected null for non-null column