程序包 ohos.data.rdb

类 RdbOpenCallback

java.lang.Object

ohos.data.rdb.RdbOpenCallback

public abstract class RdbOpenCallback
extends Object

Manages database creation, upgrade, and downgrade.

You can create a child class to implement the #onCreate, #onUpgrade, or #onOpen method. If a database already exists, it will be opened; if no database exists, a database will be created. During database upgrade, the methods of this class are also called.

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
RdbOpenCallback()

方法概要

限定符和类型	方法	说明
void	onCorruption(File databaseFile)	Called when a corruption exception occurs when the database is opened.
abstract void	onCreate(RdbStore store)	Called when the database associated with an RDB store is created.
void	onDowngrade(RdbStore store, int currentVersion, int targetVersion)	Called when the database associated with this RdbStore needs to be downgraded.
void	onOpen(RdbStore store)	Called when the database associated with an RDB store is opened.
abstract void	onUpgrade(RdbStore store, int currentVersion, int targetVersion)	Called when the database associated with an RDB store needs to be upgraded.

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

RdbOpenCallback

public RdbOpenCallback()

方法详细资料

onCreate

public abstract void onCreate(RdbStore store)

Called when the database associated with an RDB store is created.

This method creates a database and inserts initialized table data into the database.

参数:

store - Indicates the RdbStore object.

从以下版本开始:

1

onUpgrade

public abstract void onUpgrade(RdbStore store,
                               int currentVersion,
                               int targetVersion)

Called when the database associated with an RDB store needs to be upgraded.

This method is executed in a transaction. If an exception is thrown, all changes will be automatically rolled back.

参数:

store - Indicates the RdbStore object.

currentVersion - Indicates the current database version.

targetVersion - Indicates the target database version.

从以下版本开始:

1

onDowngrade

public void onDowngrade(RdbStore store,
                        int currentVersion,
                        int targetVersion)

Called when the database associated with this RdbStore needs to be downgraded.

This method is executed in a transaction. If an exception is thrown, all changes will be automatically rolled back.

参数:

store - Indicates the RdbStore object.

currentVersion - Indicates the current database version.

targetVersion - Indicates the target database version.

从以下版本开始:

1

onOpen

public void onOpen(RdbStore store)

Called when the database associated with an RDB store is opened.

参数:

store - Indicates the RdbStore object.

从以下版本开始:

1

onCorruption

public void onCorruption(File databaseFile)

Called when a corruption exception occurs when the database is opened.

参数:

databaseFile - the file representing the database on which corruption is detected.

从以下版本开始:

4