Struct ChangeColumns

pub struct ChangeColumns {
    pub pre_columns: u32,
    pub post_columns: u32,
    pub version: u32,
}

An even simpler migration which just changes the number of columns.

Fields

pre_columns: u32

The amount of columns before this migration.

post_columns: u32

The amount of columns after this migration.

version: u32

The version after this migration.

Trait Implementations

impl Migration for ChangeColumns

fn pre_columns(&self) -> u32

Number of columns in the database before the migration.

fn columns(&self) -> u32

Number of columns in database after the migration.

fn alters_existing(&self) -> bool

Whether this migration alters any existing columns. if not, then column families will simply be added and migrate will never be called.

fn version(&self) -> u32

Version of the database after the migration.

fn migrate( &mut self, _: Arc<Database>, _: &Config, _: &mut Database, _: u32, ) -> Result<()>

Migrate a source to a destination.