7

我的 ORMlite 服务运行良好。所有 CRUD 操作都可以正常工作。但是，当我向我的实体添加一个新的可为空字段时，整个事情都失败了。我得到空指针并且应用程序死亡。

这是我添加的字段：

@DatabaseField( canBeNull = true  )
private String newField;

如果我删除我的数据库并重新创建它，那么一切都很好。我想知道的是为什么一个简单的模式更改会导致这种情况？我正在考虑数据库充满数据的地方，我不希望新的可为空字段破坏它，或者这是可以预期的？

这是一个例外：

W/System.err(16955): java.sql.SQLException: Unknown field 'newField' from the Android sqlite cursor, not in:[desc, name, id]
W/System.err(16955):    at com.j256.ormlite.android.AndroidDatabaseResults.findColumn(AndroidDatabaseResults.java:97)
W/System.err(16955):    at com.j256.ormlite.field.FieldType.resultToJava(FieldType.java:793)
W/System.err(16955):    at com.j256.ormlite.stmt.mapped.BaseMappedQuery.mapRow(BaseMappedQuery.java:60)
W/System.err(16955):    at com.j256.ormlite.stmt.SelectIterator.getCurrent(SelectIterator.java:270)

这是我在更新实体类以包含以下新字段时遇到的异常。

@DatabaseField( canBeNull = true  )
private String newField;

现在看到，如果我删除新字段，我的测试用例/应用程序工作正常，那么正是这段代码破坏了事情。

[2012-07-05 22:42:00 - WishListManager] Success!
[2012-07-05 22:42:00 - WishListManagerTest] Launching instrumentation android.test.InstrumentationTestRunner on device emulator-5554
[2012-07-05 22:42:00 - WishListManagerTest] Collecting test information
[2012-07-05 22:42:02 - WishListManagerTest] Sending test information to Eclipse
[2012-07-05 22:42:02 - WishListManagerTest] Running tests...
[2012-07-05 22:42:04 - WishListManagerTest] Test run failed: Instrumentation run failed due to 'java.lang.NullPointerException'
[2012-07-05 22:42:04 - WishListManagerTest] Test run finished


07-05 21:42:02.084: I/TestRunner(16955): started: testAddDuplicateWishLists(com.tests.WishListServiceTest)
07-05 21:42:02.504: I/global(16955): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
07-05 21:42:02.524: I/global(16955): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
07-05 21:42:02.654: D/dalvikvm(16955): GC_FOR_MALLOC freed 4623 objects / 361912 bytes in 63ms
07-05 21:42:02.754: I/global(16955): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
07-05 21:42:02.764: I/global(16955): Default buffer size used in BufferedReader constructor. It would be better to be explicit if an 8k-char buffer is required.
07-05 21:42:02.774: W/System.err(16955): java.sql.SQLException: Unknown field 'newField' from the Android sqlite cursor, not in:[desc, name, id]
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.android.AndroidDatabaseResults.findColumn(AndroidDatabaseResults.java:97)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.field.FieldType.resultToJava(FieldType.java:793)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.stmt.mapped.BaseMappedQuery.mapRow(BaseMappedQuery.java:60)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.stmt.SelectIterator.getCurrent(SelectIterator.java:270)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.stmt.SelectIterator.nextThrow(SelectIterator.java:161)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.stmt.StatementExecutor.query(StatementExecutor.java:161)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.stmt.StatementExecutor.queryForAll(StatementExecutor.java:113)
07-05 21:42:02.784: W/System.err(16955):    at com.j256.ormlite.dao.BaseDaoImpl.queryForAll(BaseDaoImpl.java:237)
07-05 21:42:02.784: W/System.err(16955):    at com.test.db.WishListService.getAllWishLists(WishListService.java:42)
07-05 21:42:02.784: W/System.err(16955):    at com.test.WishListManagerActivity.setupListView(WishListManagerActivity.java:48)
07-05 21:42:02.784: W/System.err(16955):    at com.test.WishListManagerActivity.onStart(WishListManagerActivity.java:44)
07-05 21:42:02.784: W/System.err(16955):    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1129)
07-05 21:42:02.784: W/System.err(16955):    at android.app.Activity.performStart(Activity.java:3781)
07-05 21:42:02.784: W/System.err(16955):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2636)
07-05 21:42:02.784: W/System.err(16955):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-05 21:42:02.794: W/System.err(16955):    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-05 21:42:02.794: W/System.err(16955):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-05 21:42:02.794: W/System.err(16955):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-05 21:42:02.794: W/System.err(16955):    at android.os.Looper.loop(Looper.java:123)
07-05 21:42:02.794: W/System.err(16955):    at android.app.ActivityThread.main(ActivityThread.java:4627)
07-05 21:42:02.794: W/System.err(16955):    at java.lang.reflect.Method.invokeNative(Native Method)
07-05 21:42:02.794: W/System.err(16955):    at java.lang.reflect.Method.invoke(Method.java:521)
07-05 21:42:02.794: W/System.err(16955):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-05 21:42:02.794: W/System.err(16955):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-05 21:42:02.794: W/System.err(16955):    at dalvik.system.NativeStart.main(Native Method)
07-05 21:42:02.804: D/AndroidRuntime(16955): Shutting down VM
07-05 21:42:02.804: W/dalvikvm(16955): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
07-05 21:42:02.814: E/AndroidRuntime(16955): FATAL EXCEPTION: main
07-05 21:42:02.814: E/AndroidRuntime(16955): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test/com.test.WishListManagerActivity}: java.lang.NullPointerException
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.os.Looper.loop(Looper.java:123)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread.main(ActivityThread.java:4627)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at java.lang.reflect.Method.invokeNative(Native Method)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at java.lang.reflect.Method.invoke(Method.java:521)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at dalvik.system.NativeStart.main(Native Method)
07-05 21:42:02.814: E/AndroidRuntime(16955): Caused by: java.lang.NullPointerException
07-05 21:42:02.814: E/AndroidRuntime(16955):    at com.test.WishListManagerActivity.setupListView(WishListManagerActivity.java:51)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at com.test.WishListManagerActivity.onStart(WishListManagerActivity.java:44)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1129)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.Activity.performStart(Activity.java:3781)
07-05 21:42:02.814: E/AndroidRuntime(16955):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2636)
07-05 21:42:02.814: E/AndroidRuntime(16955):    ... 11 more
4

2 回答 2

6

我的 ORMlite 服务运行良好。所有 CRUD 操作都可以正常工作。但是，当我向我的实体添加一个新的可为空字段时，整个事情都失败了。

所以ORMLite例外对我来说似乎很有帮助：

java.sql.SQLException: Unknown field 'newField' from the Android sqlite cursor,
    not in:[desc, name, id]

您正在尝试提取该newField字段，但它不在数据库表中。这向我表明您没有更新数据库的架构。它在表中的唯一字段是desc、name和id。

升级数据库表的代码尚未运行，或者无法正常工作。我会看一下我写的关于如何在 Android 下升级架构的文档页面。

不幸的是，Sqlite 只支持少数ALTER TABLE命令，但ADD COLUMN 它就是其中之一。

于 2012-07-06T13:34:13.093 回答
0

我用升级数据库版本解决了这个问题！您应该知道在数据库中添加或删除..时应该升级数据库版本！

例子：

if the current version is = 2 after the change should be 3 ;
于 2020-07-20T07:36:55.400 回答