When you insert a struct, all fields, including foreign keys of joins, will be inserted.

Check the API for details.

For selectable fields in a struct that are None the default value will be inserted. If you have not defined a default value in your database you must ensure that the field in the struct can't be None. This can be done through prior validation.

The insert behaviour depends on the type and mapping of a field:

# #![allow(unused_variables)]
#fn main() {
use toql::prelude::Toql;
#   #[derive(Toql)]
#   struct Phone {
#   
#   	#[toql(key)]
#   	number: String,
#   	prepaid : Option<bool>
#   }
#   
#   #[derive(Toql)]
#   struct Address {
#   	#[toql(key)]
#   	id: u64,
#   	street: Option<String>
#   }
  
#[derive(Toql)]
struct User {
    #[toql(key)]
    id: u64,                    
    
    username: String,		// Value
    realname: Option<String>,	// Default or value
    address: Option<Option<String>>,// Nullable column: Default, value or NULL

    #[toql(preselect)]
    info: Option<String>, 	// Nullable column: Value or NULL

    #[toql(join)]
    address1: Option<Address>, 	// Selectable inner Join: Foreign key is inserted or default

    #[toql(join)]
    address2: Option<Option<Address>>,// Selectable left join: Default, value or NULL

    #[toql(join)]
    address3: Address, 		// Inner Join: Foreign key or default

    #[toql(join, preselect)]
    address4: Option<Address>,	// Selectable inner join: Foreign key or default

    #[toql(merge)]
    phones1: Vec<Phone>,		// No change on table 'User'

    #[toql(merge)]
    phones2: Option<Vec<Phone>> // No change on table 'User'
}
#}

When the path list requires to insert a dependency too, left joins and optional merges will only be inserted, if they contains a value.