belongs to Maven artifact android.arch.persistence.room:runtime:1.1.0-beta2
Migration
public
abstract
class
Migration
extends Object
| java.lang.Object | |
| ↳ | android.arch.persistence.room.migration.Migration |
Base class for a database migration.
Each migration can move between 2 versions that are defined by startVersion and
endVersion.
A migration can handle more than 1 version (e.g. if you have a faster path to choose when going version 3 to 5 without going to version 4). If Room opens a database at version 3 and latest version is >= 5, Room will use the migration object that can migrate from 3 to 5 instead of 3 to 4 and 4 to 5.
If there are not enough migrations provided to move from the current version to the latest version, Room will clear the database and recreate so even if you have no changes between 2 versions, you should still provide a Migration object to the builder.
Summary
Fields | |
|---|---|
public
final
int |
endVersion
|
public
final
int |
startVersion
|
Public constructors | |
|---|---|
Migration(int startVersion, int endVersion)
Creates a new migration between |
|
Public methods | |
|---|---|
abstract
void
|
migrate(SupportSQLiteDatabase database)
Should run the necessary migrations. |
Inherited methods | |
|---|---|
Fields
Public constructors
Migration
Migration (int startVersion,
int endVersion)Creates a new migration between startVersion and endVersion.
| Parameters | |
|---|---|
startVersion |
int: The start version of the database. |
endVersion |
int: The end version of the database after this migration is applied.
|
Public methods
migrate
void migrate (SupportSQLiteDatabase database)
Should run the necessary migrations.
This class cannot access any generated Dao in this method.
This method is already called inside a transaction and that transaction might actually be a
composite transaction of all necessary Migrations.
| Parameters | |
|---|---|
database |
SupportSQLiteDatabase: The database instance
|
Classes