程序包 ohos.data.orm

类 OrmMigration

java.lang.Object

ohos.data.orm.OrmMigration

public abstract class OrmMigration
extends Object

Upgrades and downgrades databases.

If you need to modify the database structure, for example, add a table or field, you need to create a database class, specify the new database version, and then prepare an SQL statement for upgrading or downgrading between the start and end versions specified by OrmMigration(int, int). The ORM annotation processor will identify the start and end version, and execute the specified SQL statement to complete the upgrade or downgrade.

从以下版本开始:

1

SystemCapability

SystemCapability.Data#DATA_APPDATAMGR

构造器概要

构造器

构造器	说明
OrmMigration(int beginVersion, int endVersion)	Constructor of this class for upgrading or downgrading from the start version to the end version.

方法概要

限定符和类型	方法	说明
int	getBeginVersion()	Obtains the value of variable beginVersion.
int	getEndVersion()	Obtains the value of variable endVersion.
abstract void	onMigrate(RdbStore store)	Upgrades or downgrades the database.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

OrmMigration

public OrmMigration(int beginVersion,
                    int endVersion)

Constructor of this class for upgrading or downgrading from the start version to the end version.

参数:

beginVersion - Indicates the start version.

endVersion - Indicates the end version.

从以下版本开始:

1

方法详细资料

getBeginVersion

public int getBeginVersion()

Obtains the value of variable beginVersion.

返回:

Returns the value of variable beginVersion.

getEndVersion

public int getEndVersion()

Obtains the value of variable endVersion.

返回:

Returns the value of variable endVersion.

onMigrate

public abstract void onMigrate(RdbStore store)

Upgrades or downgrades the database.

You need to specify the SQL statement for upgrading or downgrading from the start version to the end version.

参数:

store - Indicates the handle of the relational database.

从以下版本开始:

1

另请参阅:

RdbStore