Struct Migration 

pub struct Migration { /* private fields */ }

One numbered change to the app’s database, with its declared kind. Clones retain the same callbacks across bootstrap and database opening.

Implementations

impl Migration

pub fn addition( version: u32, name: &'static str, sql: &'static str, ) -> Migration

SQL that adds tables or columns, or changes only local objects. A runtime breaking classification refuses the whole migration batch.

pub fn addition_with<F>(version: u32, name: &'static str, f: F) -> Migration

where F: Fn(&MigrationContext<'_>) -> Result<(), DbError> + Send + Sync + 'static,

Code that adds tables or columns, or changes only local objects.

pub fn breaking( version: u32, name: &'static str, sql: &'static str, old_writes: OldWrites, ) -> Migration

Breaking SQL with an explicit choice for late old-version writes. An addition or local-only classification refuses the whole batch.

A breaking migration cannot omit the old-write choice:

use coven_database::Migration;
Migration::breaking(2, "rename", "ALTER TABLE notes RENAME COLUMN title TO name");

pub fn breaking_with<F>( version: u32, name: &'static str, f: F, old_writes: OldWrites, ) -> Migration

where F: Fn(&MigrationContext<'_>) -> Result<(), DbError> + Send + Sync + 'static,

Breaking code, including backfills and rebuilds, with its old-write choice.

use coven_database::Migration;
Migration::breaking_with(2, "backfill", |context| {
    context.execute_batch("UPDATE notes SET title=upper(title)")?;
    Ok(())
});

Trait Implementations

impl Clone for Migration

fn clone(&self) -> Migration

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.