pub trait SaveChangesDsl<Conn> {
// Provided method
fn save_changes<T>(self, connection: &mut Conn) -> QueryResult<T>
where Self: Sized,
Conn: UpdateAndFetchResults<Self, T> { ... }
}
Expand description
Sugar for types which implement both AsChangeset
and Identifiable
On backends which support the RETURNING
keyword,
foo.save_changes(&conn)
is equivalent to
update(&foo).set(&foo).get_result(&conn)
.
On other backends, two queries will be executed.
§Example
#[derive(Queryable, Debug, PartialEq)]
struct Animal {
id: i32,
species: String,
legs: i32,
name: Option<String>,
}
#[derive(AsChangeset, Identifiable)]
#[diesel(table_name = animals)]
struct AnimalForm<'a> {
id: i32,
name: &'a str,
}
let form = AnimalForm { id: 2, name: "Super scary" };
let changed_animal = form.save_changes(connection)?;
let expected_animal = Animal {
id: 2,
species: String::from("spider"),
legs: 8,
name: Some(String::from("Super scary")),
};
assert_eq!(expected_animal, changed_animal);
Provided Methods§
sourcefn save_changes<T>(self, connection: &mut Conn) -> QueryResult<T>where
Self: Sized,
Conn: UpdateAndFetchResults<Self, T>,
fn save_changes<T>(self, connection: &mut Conn) -> QueryResult<T>where
Self: Sized,
Conn: UpdateAndFetchResults<Self, T>,
See the trait documentation.