More generic CRUD. RUST, Diesel - postgresql

Question

is it possible to create more generic queries using diesel?
I know how to create update or delete for every properties. But my point is create generic update for many structures.
My models:
#[derive(Associations, Identifiable, Queryable, PartialEq, Debug)]
#[diesel(belongs_to(User))]
#[diesel(table_name = books)]
pub struct Book {
pub id: i32,
pub user_id: i32,
pub title: String,
pub body: String,
pub book_description: String,
pub book_image: Option<String>,
pub publish_day: chrono::NaiveDateTime,
}
#[derive(Associations, Identifiable, Queryable, PartialEq, Debug)]
#[diesel(belongs_to(Book))]
#[diesel(table_name = book_comments)]
pub struct BookComment {
pub id: i32,
pub book_id: i32,
pub body: String,
pub publish_day: chrono::NaiveDateTime,
}
My schema:
diesel::table! {
books (id) {
id -> Int4,
user_id -> Int4,
title -> Varchar,
body -> Text,
book_description -> Varchar,
book_image -> Nullable<Varchar>,
publish_day -> Timestamp,
}
}
diesel::table! {
book_comments (id) {
id -> Int4,
book_id -> Int4,
body -> Varchar,
publish_day -> Timestamp,
}
}
Working wersion:
pub fn upate<T>(&mut self, book_id: &i32, title: &str) -> Book {
let result = diesel::update(books::table)
.filter(book::id.eq(&book_id))
.set(book::title.eq(title))
.get_result::<Book>(&mut self.connection)
.expect("Failed to update book");
result
}
I'm trying something like this:
pub fn upate<T, U, P: Table, S>(&mut self, find_by: &T, change: U, target_table: Table,change_param: &S) -> Book {
let result = diesel::update(target_table)
.filter(find_by.eq(&book_id))
.set(S.eq(change))
.get_result::<U>(&mut self.connection)
.expect("Failed to update book");
result
But of course doesn't work. Is this possible?
Little help with solution.

Answer 1

I did this using macro, this is a snippet from the code I used
#[macro_export]
macro_rules! get_by_id {
($table:ident,$m:ident,$pool:ident,$id:ident) => {
{
let conn = $pool.get()?;
let res = $table::table
.filter($table::columns::id.eq($id))
.get_result::<$m>(&conn)?;
Ok(res) as Result<$m, Error>
}
};
}
Edit: can be used like this:
let user = get_by_id!(schema::users, User, pool, user_id)?;