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我正在将 SQLite 数据库文件从服务器下载到用户的 Android 设备。下载后，我使用下载的数据库在本地数据库中插入或替换一些表。我为此使用 ORMLite 4.47。

首先，我将数据库文件附加到 DatabaseConnection：

DatabaseConnection con = null;
con = conSrc.getReadWriteConnection();
con.executeStatement("attach database '" + localDatabase.getAbsolutePath() + "' as '" + localDb + "'", DatabaseConnection.DEFAULT_RESULT_FLAGS);
con.executeStatement("attach database '" + downloadedDatabase.getAbsolutePath() + "' as '" + remoteDb + "'", DatabaseConnection.DEFAULT_RESULT_FLAGS);

附加数据库后，我创建以下查询以从下载的数据库 (remoteDb) 复制到本地数据库 (localDb)：

INSERT OR REPLACE INTO localDb.table_items (createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6) SELECT createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6 FROM remoteDb.table_items

之后，我从 ORMLite 执行以下函数：

con.executeStatement(query, flags);

该功能在 Android 4.1（带有 SQLite 3.7.11）及更高版本上运行良好。但我在 Android 版本 4.0 和 4.0.3（使用 SQLite 3.7.4）上收到以下错误：

09-13 15:51:19.852: E/com.example.controller(1028): java.sql.SQLException: Problems executing INSERT OR REPLACE INTO localDb.table_items (createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6) SELECT createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6 FROM remoteDb.table_items Android statement: INSERT OR REPLACE INTO localDb.table_items (createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6) SELECT createdAt_device, updatedAt_device, _id, column_1, column_2, column_3, column_4, column_5, column_6 FROM remoteDb.table_items
09-13 15:51:19.852: E/com.example.controller(1028):     at com.j256.ormlite.misc.SqlExceptionUtil.create(SqlExceptionUtil.java:22)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.j256.ormlite.android.AndroidCompiledStatement.execSql(AndroidCompiledStatement.java:185)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.j256.ormlite.android.AndroidDatabaseConnection.executeStatement(AndroidDatabaseConnection.java:134)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller$DatabaseTransferHandler.executeDatabaseTransfers(contoller.java:763)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller$DatabaseTransferHandler.access$0(contoller.java:740)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.transferTables(contoller.java:494)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.addElement(contoller.java:132)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.addOrRemoveElements(contoller.java:109)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.addElements(contoller.java:147)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.download(contoller.java:254)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller.access$3(controller.java:204)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller$2.doInBackground(contoller.java:468)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.example.controller$2.doInBackground(contoller.java:1)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.os.AsyncTask$2.call(AsyncTask.java:264)
09-13 15:51:19.852: E/com.example.controller(1028):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
09-13 15:51:19.852: E/com.example.controller(1028):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
09-13 15:51:19.852: E/com.example.controller(1028):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
09-13 15:51:19.852: E/com.example.controller(1028):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
09-13 15:51:19.852: E/com.example.controller(1028):     at java.lang.Thread.run(Thread.java:856)
09-13 15:51:19.852: E/com.example.controller(1028): Caused by: android.database.sqlite.SQLiteDatabaseLockedException: database is locked
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteStatement.native_executeSql(Native Method)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:90)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1899)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1839)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.beginTransaction(SQLiteDatabase.java:661)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.beginTransactionNonExclusive(SQLiteDatabase.java:576)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteStatement.acquireAndLock(SQLiteStatement.java:247)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:84)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1899)
09-13 15:51:19.852: E/com.example.controller(1028):     at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1889)
09-13 15:51:19.852: E/com.example.controller(1028):     at com.j256.ormlite.android.AndroidCompiledStatement.execSql(AndroidCompiledStatement.java:183)
09-13 15:51:19.852: E/com.example.controller(1028):     ... 18 more

我怎么解决这个问题？是否有更好的方法将大量信息下载到设备？

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1 回答 1

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我是这个问题作者的同事，我设法找到了避免这个问题的方法。我想我会把它贴在这里，以防其他人遇到同样的问题。

具有非常特定操作系统版本的 Android 设备似乎对以下 Ormlite 命令序列存在问题：

DatabaseConnection con = null;
con = conSrc.getReadWriteConnection();
con.executeStatement("attach database '" + localDatabase.getAbsolutePath() + "' as '" + localDb + "'", DatabaseConnection.DEFAULT_RESULT_FLAGS);
con.executeStatement("attach database '" + downloadedDatabase.getAbsolutePath() + "' as '" + remoteDb + "'", DatabaseConnection.DEFAULT_RESULT_FLAGS);

我不知道这是由这些设备上预装的 SQLite3 版本引起的，还是由其他原因引起的。

现在我们可以避免这种情况，因为我们可以（幸运地）完全避免在这种情况下使用 Ormlite。SQLite 语句“ATTACH DATABASE”不需要在 DatabaseConnection 实例上执行 - 它可以在本地数据库文件上执行。所以代替前一个块，只需要这个语句：

db.execSQL("ATTACH DATABASE '" + tempDb.getAbsolutePath() + "' AS '" + remoteDb + "'");

db本地数据库的SQLiteDatabase实例在哪里。SQLite 文档指出：

“ATTACH DATABASE 语句将另一个数据库文件添加到当前数据库连接。”

这就是为什么不需要DatabaseConnection实例的原因。

于 2013-10-15T15:04:14.720 回答