Trait ethcore_util::migration::SimpleMigration
[−]
[src]
pub trait SimpleMigration: 'static { fn columns(&self) -> Option<u32>; fn version(&self) -> u32; fn simple_migrate(&mut self,
key: Vec<u8>,
value: Vec<u8>)
-> Option<(Vec<u8>, Vec<u8>)>; }
A simple migration over key-value pairs.
Required Methods
fn columns(&self) -> Option<u32>
Number of columns in database after the migration.
fn version(&self) -> u32
Version of database after the migration.
fn simple_migrate(&mut self,
key: Vec<u8>,
value: Vec<u8>)
-> Option<(Vec<u8>, Vec<u8>)>
key: Vec<u8>,
value: Vec<u8>)
-> Option<(Vec<u8>, Vec<u8>)>
Should migrate existing object to new database.
Returns None
if the object does not exist in new version of database.