如何修复尝试进行查询时抛出的 SQLiteException？

Question

我有一个字典应用程序使用我提供的数据库完全脱机工作。为了能够使用数据库，我应用了一个我在开发者博客上看到的解决方案。可以从thislink中参考。解决方案基本上是从资产文件夹中复制数据库并使用它。它在大多数设备上都没有问题，但有些用户在尝试查询数据库时遇到崩溃。我附上了我收到的堆栈跟踪以及从 Asus ZenFone 5 (ZE620KL) (ASUS_X00QD) 发送的崩溃报告。我的问题是：我正在应用的实践（使用位于资产文件夹中的现有数据库）是否存在问题？我该怎么做才能避免这种异常？

  at android.database.sqlite.SQLiteConnection.nativePrepareStatement (Native Method)
  at android.database.sqlite.SQLiteConnection.acquirePreparedStatement (SQLiteConnection.java:903)
  at android.database.sqlite.SQLiteConnection.prepare (SQLiteConnection.java:514)
  at android.database.sqlite.SQLiteSession.prepare (SQLiteSession.java:588)
  at android.database.sqlite.SQLiteProgram.<init> (SQLiteProgram.java:58)
  at android.database.sqlite.SQLiteQuery.<init> (SQLiteQuery.java:37)
  at android.database.sqlite.SQLiteDirectCursorDriver.query (SQLiteDirectCursorDriver.java:46)
  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory (SQLiteDatabase.java:1408)
  at android.database.sqlite.SQLiteDatabase.queryWithFactory (SQLiteDatabase.java:1255)
  at android.database.sqlite.SQLiteDatabase.query (SQLiteDatabase.java:1126)
  at android.database.sqlite.SQLiteDatabase.query (SQLiteDatabase.java:1294)
  at com.tur_cirdictionary.turkish_circassiandictionary.data.WordProvider.query (WordProvider.java:52)
  at android.content.ContentProvider.query (ContentProvider.java:1064)
  at android.content.ContentProvider.query (ContentProvider.java:1156)
  at android.content.ContentProvider$Transport.query (ContentProvider.java:241)
  at android.content.ContentResolver.query (ContentResolver.java:809)
  at android.content.ContentResolver.query (ContentResolver.java:758)
  at com.tur_cirdictionary.turkish_circassiandictionary.MainActivity.showSuggestionsForQuery (MainActivity.java:245)
  at com.tur_cirdictionary.turkish_circassiandictionary.MainActivity.access[=10=]0 (MainActivity.java:37)
  at com.tur_cirdictionary.turkish_circassiandictionary.MainActivity.onQueryTextChange (MainActivity.java:178)
  at android.widget.SearchView.onTextChanged (SearchView.java:1250)
  at android.widget.SearchView.access00 (SearchView.java:98)
  at android.widget.SearchView.onTextChanged (SearchView.java:1776)
  at android.widget.TextView.sendOnTextChanged (TextView.java:9784)
  at android.widget.TextView.handleTextChanged (TextView.java:9881)
  at android.widget.TextView$ChangeWatcher.onTextChanged (TextView.java:12539)
  at android.text.SpannableStringBuilder.sendTextChanged (SpannableStringBuilder.java:1263)
  at android.text.SpannableStringBuilder.replace (SpannableStringBuilder.java:575)
  at android.text.SpannableStringBuilder.replace (SpannableStringBuilder.java:506)
  at android.text.SpannableStringBuilder.replace (SpannableStringBuilder.java:36)
  at android.view.inputmethod.BaseInputConnection.replaceText (BaseInputConnection.java:843)
  at android.view.inputmethod.BaseInputConnection.commitText (BaseInputConnection.java:197)
  at com.android.internal.widget.EditableInputConnection.commitText (EditableInputConnection.java:183)
  at com.android.internal.view.IInputConnectionWrapper.executeMessage (IInputConnectionWrapper.java:341)
  at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage (IInputConnectionWrapper.java:85)
  at android.os.Handler.dispatchMessage (Handler.java:106)
  at android.os.Looper.loop (Looper.java:198)
  at android.app.ActivityThread.main (ActivityThread.java:6732)
  at java.lang.reflect.Method.invoke (Native Method)
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:493)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:858)

WordContract.java

package com.tur_cirdictionary.turkish_circassiandictionary.data;

import android.content.ContentResolver;
import android.net.Uri;
import android.provider.BaseColumns;

public final class WordContract {

    public static final String CONTENT_AUTHORITY =
            "com.tur_cirdictionary.turkish_circassiandictionary";

    public static final Uri BASE_CONTENT_URI = Uri.parse("content://" + CONTENT_AUTHORITY);

    public static final String PATH_WORDS = "words";

    private WordContract() {}

    public static class WordEntry implements BaseColumns {

        public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, PATH_WORDS);

        public static final String CONTENT_LIST_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + "/" +
                CONTENT_AUTHORITY + PATH_WORDS;

        public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/" +
                CONTENT_AUTHORITY + "/" + PATH_WORDS;

        public static final String TABLE_NAME = "words";
        public static final String _ID = BaseColumns._ID;
        public static final String COLUMN_NAME_CIRCASSIAN = "circassian";
        public static final String COLUMN_NAME_TURKISH = "turkish";
    }
}

WordDbHelper.java

package com.tur_cirdictionary.turkish_circassiandictionary.data;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import com.tur_cirdictionary.turkish_circassiandictionary.data.WordContract.WordEntry;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class WordDbHelper extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 1;
    private static String DATABASE_PATH
            = "/data/data/com.tur_cirdictionary.turkish_circassiandictionary/databases/";
    private static final String DATABASE_NAME = "Cir_Tur.sqlite";
    private SQLiteDatabase database;
    private final Context context;

    public WordDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    public void createDatabase() {
        boolean dbExist = checkDataBase();
        if (dbExist) {
            //Cool. Don't do anything.
        } else {
            try {
                this.getReadableDatabase();
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }

    private boolean checkDataBase() {
        SQLiteDatabase checkDB = null;
        try {
            String path = DATABASE_PATH + DATABASE_NAME;
            checkDB = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        } catch (SQLException e) {
            //Database does not exist
        }
        if (checkDB != null) {
            checkDB.close();
        }
        return checkDB != null;
    }

    private void copyDataBase() throws IOException {
        InputStream inputStream = context.getAssets().open(DATABASE_NAME);
        String outFileName = DATABASE_PATH + DATABASE_NAME;
        OutputStream outputStream = new FileOutputStream(outFileName);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, length);
        }
        outputStream.flush();
        outputStream.close();
        inputStream.close();
    }

    public SQLiteDatabase openDatabase() {
        String path = DATABASE_PATH + DATABASE_NAME;
        database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        return database;
    }

    @Override
    public synchronized void close() {
        if (database != null) {
            database.close();
        }
        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    private static final String SQL_CREATE_WORDS =
            "CREATE TABLE  " + WordEntry.TABLE_NAME + " ("
                    + WordEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + WordEntry.COLUMN_NAME_CIRCASSIAN + " TEXT, "
                    + WordEntry.COLUMN_NAME_TURKISH + " TEXT)";

    private static final String SQL_DELETE_WORDS =
            "DROP TABLE IF EXISTS " + WordContract.WordEntry.TABLE_NAME;
}

WordProvider.java

package com.tur_cirdictionary.turkish_circassiandictionary.data;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import com.tur_cirdictionary.turkish_circassiandictionary.data.WordContract.WordEntry;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class WordDbHelper extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 1;
    private static String DATABASE_PATH
            = "/data/data/com.tur_cirdictionary.turkish_circassiandictionary/databases/";
    private static final String DATABASE_NAME = "Cir_Tur.sqlite";
    private SQLiteDatabase database;
    private final Context context;

    public WordDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    public void createDatabase() {
        boolean dbExist = checkDataBase();
        if (dbExist) {
            //Cool. Don't do anything.
        } else {
            try {
                this.getReadableDatabase();
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }

    private boolean checkDataBase() {
        SQLiteDatabase checkDB = null;
        try {
            String path = DATABASE_PATH + DATABASE_NAME;
            checkDB = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        } catch (SQLException e) {
            //Database does not exist
        }
        if (checkDB != null) {
            checkDB.close();
        }
        return checkDB != null;
    }

    private void copyDataBase() throws IOException {
        InputStream inputStream = context.getAssets().open(DATABASE_NAME);
        String outFileName = DATABASE_PATH + DATABASE_NAME;
        OutputStream outputStream = new FileOutputStream(outFileName);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, length);
        }
        outputStream.flush();
        outputStream.close();
        inputStream.close();
    }

    public SQLiteDatabase openDatabase() {
        String path = DATABASE_PATH + DATABASE_NAME;
        database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        return database;
    }

    @Override
    public synchronized void close() {
        if (database != null) {
            database.close();
        }
        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    private static final String SQL_CREATE_WORDS =
            "CREATE TABLE  " + WordEntry.TABLE_NAME + " ("
                    + WordEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + WordEntry.COLUMN_NAME_CIRCASSIAN + " TEXT, "
                    + WordEntry.COLUMN_NAME_TURKISH + " TEXT)";

    private static final String SQL_DELETE_WORDS =
            "DROP TABLE IF EXISTS " + WordContract.WordEntry.TABLE_NAME;

}

MainActivity.java

package com.tur_cirdictionary.turkish_circassiandictionary.data;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import com.tur_cirdictionary.turkish_circassiandictionary.data.WordContract.WordEntry;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class WordDbHelper extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 1;
    private static String DATABASE_PATH
            = "/data/data/com.tur_cirdictionary.turkish_circassiandictionary/databases/";
    private static final String DATABASE_NAME = "Cir_Tur.sqlite";
    private SQLiteDatabase database;
    private final Context context;

    public WordDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    public void createDatabase() {
        boolean dbExist = checkDataBase();
        if (dbExist) {
            //Cool. Don't do anything.
        } else {
            try {
                this.getReadableDatabase();
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }
        }
    }

    private boolean checkDataBase() {
        SQLiteDatabase checkDB = null;
        try {
            String path = DATABASE_PATH + DATABASE_NAME;
            checkDB = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        } catch (SQLException e) {
            //Database does not exist
        }
        if (checkDB != null) {
            checkDB.close();
        }
        return checkDB != null;
    }

    private void copyDataBase() throws IOException {
        InputStream inputStream = context.getAssets().open(DATABASE_NAME);
        String outFileName = DATABASE_PATH + DATABASE_NAME;
        OutputStream outputStream = new FileOutputStream(outFileName);
        byte[] buffer = new byte[1024];
        int length;
        while ((length = inputStream.read(buffer)) > 0) {
            outputStream.write(buffer, 0, length);
        }
        outputStream.flush();
        outputStream.close();
        inputStream.close();
    }

    public SQLiteDatabase openDatabase() {
        String path = DATABASE_PATH + DATABASE_NAME;
        database = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
        return database;
    }

    @Override
    public synchronized void close() {
        if (database != null) {
            database.close();
        }
        super.close();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    private static final String SQL_CREATE_WORDS =
            "CREATE TABLE  " + WordEntry.TABLE_NAME + " ("
                    + WordEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + WordEntry.COLUMN_NAME_CIRCASSIAN + " TEXT, "
                    + WordEntry.COLUMN_NAME_TURKISH + " TEXT)";

    private static final String SQL_DELETE_WORDS =
            "DROP TABLE IF EXISTS " + WordContract.WordEntry.TABLE_NAME;
}

如有必要，她是整个项目的link。

Answer 1

我不知道这是否是您问题的原因，但是当我在 SQLite 中遇到类似的间歇性问题时，结果证明是 Android（或 Eclipse）正在压缩数据库使用 Assets 文件夹编译时的文件。解决方案是为文件提供 Android 无法压缩的文件类型的扩展名，例如扩展名为 .jpg 的图像文件。这听起来很奇怪，但我将我的数据库文件作为 mydb.jpg 放在 Assets 中，然后在 CopyDatabase 方法中，它将扩展名更改为 mydb.db 并将其存储在 /data/data/databases app 文件夹中。

Answer 2

Is there a problem on the practice I'm applying (Using the existing database located in the assets folder)?

并非如此，因为这是一种推荐且经常使用的技术。但是，如果实施不当，可能会出现问题，尤其是现在。

根据快速搜索，设备的 OS 是 Android 8.0 (Oreo)，可升级到 Android 9.0 (Pie); ZenUI 5

在使用AndroidPie时肯定会发现1个问题，这很可能是您遇到的问题。

原因是在调用 copyDatabase 方法之前使用了 this.getReadableDatabase();。

As Android Pie 默认打开 WAL（预写日志记录）两个文件 -wal 和 -shm 文件被创建。这些剩余的会导致冲突，因为它们与刚刚复制的数据库不匹配。我相信最终的结果是删除复制的数据库并创建一个全新的数据库以提供可用的数据库。因此，不存在 table 或基础数据。这通常会导致 table not found error/exception，通常在尝试访问 table 不存在的数据时。

What can I do to avoid this exception?

修复 1

简单但不推荐的修复方法是覆盖 SQLiteOpenhelper 的 onConfigure 方法 WordDbHelper.java 以调用 disableWriteAheadLogging 方法。

但是，应用此修复意味着您放弃了 Write-Ahead Logging 的优点。

修复 2

正确的解决方法是在复制之前不使用 getReadableDatabase。这似乎是一个简单问题的历史修复。即data/data/the_package/目录下的一个包，对于一个新安装的App，没有databases 目录。因此 getWritableDatabase（或 getReabableDatabase，如果可以的话，它会获取 writable 数据库）创建目录以及随后被覆盖的数据库。

App 应该做的是检查目录是否存在然后创建它，这一切都可以在 checkDataBase 方法中使用类似 :-

private boolean checkDataBase() {

    File db = new File(DATABASE_PATH + DATABASE_NAME);
    if(db.exists()) return true;
    File dir = new File(db.getParent());
    if (!dir.exists()) {
        dir.mkdirs();
    }
    return false;
}

请注意，您还应该从 createDatabase 方法中删除行 this.getReadableDatabase();。

虽然可能不是问题，但更明智的做法是永远不要对数据库路径进行硬编码，而是使用 Context class' getDatabasePath 方法（如果使用standard/recommended 数据库的位置）。例如

private boolean checkDataBase() {

    File db = new File(context.getDatabasePath(DBNAME)); //<<<<<<<<<< CHANGED
    if(db.exists()) return true;
    File dir = new File(db.getParent());
    if (!dir.exists()) {
        dir.mkdirs();
    }
    return false;
}

备注

来自提供的堆栈跟踪以及 MainActivity.java、WordProvidr.java 和 WordDBHelper 有看似相同的代码，无法确定确切原因。因此，以上是可能的原因或可能发生的原因。

如何修复尝试进行查询时抛出的 SQLiteException？

How to fix SQLiteException thrown while trying to make a query?

android

android-sqlite

android-contentprovider

修复 1

修复 2

备注