Trait reindeer::AutoIncrementEntity

pub trait AutoIncrementEntity: Entity<Key = u32> {
    // Required methods
    fn get_next_key(db: &Db) -> Result<u32>;
    fn save_next(&mut self, db: &Db) -> Result<u32>;
}

AutoIncrementEntity is a trait aimed to automatically be implemented on Entities that have u32 as their Key type.

It provides the save_next() method that updates the key of the entity with a new, incremented one before saving it to the database.

Required Methods

fn get_next_key(db: &Db) -> Result<u32>

Returns a new key that is currently not used in the store

fn save_next(&mut self, db: &Db) -> Result<u32>

Saves the entity to the database after having modified its key to an auto-incremented one.

Example

let m_struct = MyStruct { key : 0, prop9 : 44};
m_struct.save_next(&db)?; // will have key 0
let m_struct_2 = MyStruct { key : 0, prop9 :59};
m_struct_2.save_next(&db)?; // creates a new entry with key 1, and so on
// m_struct2.key is now 1

Implementors

impl<T> AutoIncrementEntity for Twhere T: Entity<Key = u32>,