Macro mutation_object 

macro_rules! mutation_object {
    (
        $(#[doc = $glob_doc: expr])*
        $mutation_name: ident {
            $($entity_name: ident (
                $(insert = $insert: ident)?
                $($(,)? update = $update: ident)?
                $($(,)? delete = $delete: ident)?
                $(,)?
            )$(,)?)*
        }
    ) => { ... };
}

Macro to register the main mutation object

Annotated example

#[macro_use]
#[derive(WundergraphEntity, Identifiable)]
#[table_name = "heros"]
pub struct Hero {
    id: i32,
    name: String,
    species: HasOne<i32, Species>,
}

#[derive(Insertable, GraphQLInputObject)]
#[table_name = "heros"]
pub struct NewHero {
    name: String,
    species: i32,
}

#[derive(AsChangeset, Identifiable, GraphQLInputObject)]
#[table_name = "heros"]
pub struct HeroChangeset {
    id: i32,
    name: String,
}

wundergraph::mutation_object! {
    // The main mutation object. The provided name
    // maps directly to the generated struct which
    // could be used then as juniper GraphQL struct

    /// An optional doc comment describing the main mutation object
    /// Rendered as GraphQL description
    Mutation {
        // Register mutations for a wundergraph GraphQL entity
        //
        // Each field has a set of optional arguments:
        //  * insert: Specifies the used insert handler.
        //    Possible values: a struct implementing
        //    HandleInsert and HandleBatchInsert
        //    If not set or set to false no insert mutation is
        //    generated for the current entity
        //  * update: Specifies the used update handler.
        //    Possible values: a struct implementing
        //    HandleUpdate.
        //    If not set or set to false no update mutation is
        //    generated for the current entity
        //  * delete: Specifies the used delete handler.
        //    Possible values: true, false or a struct implementing
        //    HandleDelete.
        //    If not set or set to fals no delete mutation is generatet,
        //    if set to true a default delete mutation based on the
        //    primary keys is generated
        //
        // At least on of the arguments in required
        Hero(insert = NewHero, update = HeroChangeset, delete = true),
        Species(insert = false, update = false, delete = true)
    }
}