Question

我hava应用程序，它有数据库，发布后。我在我的数据库中添加了一些表。

如果客户在市场上更新此应用程序之前，如何使用已安装手机的旧数据库轻松更新新数据库。

这是我的代码。我应该在onUpgrade写一下什么？

public class DataBaseHelper extends SQLiteOpenHelper 
    { 

    //destination path (location) of our database on device 
    private static String DB_PATH = "";  
    private static String DB_NAME ="sorubankasi.sqlite";// Database name 
    private SQLiteDatabase mDataBase;  
    private final Context mContext; 
    private static final int DATABASE_VERSION = 2;// new versiyon
    private static final String tag = "stk"; 

    public DataBaseHelper(Context context)  
    { 
        super(context, DB_NAME, null, DATABASE_VERSION);// 1? its old Database Version 
        DB_PATH = "/data/data/" + context.getPackageName() + "/databases/"; 
        this.mContext = context; 
    }    

    public void createDataBase() throws IOException 
    { 

        boolean mDataBaseExist = checkDataBase(); 
        if(!mDataBaseExist) 
        { 
            this.getReadableDatabase(); 
            this.close(); 
            try  
            { 
                copyDataBase(); 
            }  
            catch (IOException mIOException)  
            { 
                throw new Error("ErrorCopyingDataBase"); 
            } 
        } 
    } 


        //Check that the database exists here: /data/data/your package/databases/Da Name 
        private boolean checkDataBase() 
        { 
            File dbFile = new File(DB_PATH + DB_NAME); 
            //Log.v("dbFile", dbFile + "   "+ dbFile.exists()); 
            return dbFile.exists(); 
        } 

        //Copy the database from assets 
        private void copyDataBase() throws IOException 
        { 
            InputStream mInput = mContext.getAssets().open(DB_NAME); 
            String outFileName = DB_PATH + DB_NAME; 
            OutputStream mOutput = new FileOutputStream(outFileName); 
            byte[] mBuffer = new byte[1024]; 
            int mLength; 
            while ((mLength = mInput.read(mBuffer))>0) 
            { 
                mOutput.write(mBuffer, 0, mLength); 
            } 
            mOutput.flush(); 
            mOutput.close(); 
            mInput.close(); 
        } 

        //Open the database, so we can query it 
        public boolean openDataBase() throws SQLException 
        { 
            String mPath = DB_PATH + DB_NAME; 
            //Log.v("mPath", mPath); 
            mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.CREATE_IF_NECESSARY); 
            //mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS); 

            Log.d(tag, "opendatabase " + mDataBase.getVersion());
            return mDataBase != null; 
        } 

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

        @Override
        public void onCreate(SQLiteDatabase arg0) {

        }

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

        }}

Answer 1

如果您正在使用SqliteOpenHelper，则需要将数据库版本增加到新版本。然后，您将获得使用数据库实例和新版本以及版本调用的方法onUpgrade()数据库正在更新。

@Override
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    //create upgrades needed between the two versions "oldVersion" to "newVersion"
    db.execSQL(newTableQuery);
    db.execSQL(dropTableQuery);
  }

否则，如果您在不使用SqliteOpenHelper的情况下直接使用开放式数据库，则必须通过选中＆＃34; yourDatabaseInstance.getVersion()＆＃34;来检查数据库版本。如果数据库版本低于特定版本，请使用＆＃34; yourDatabaseInstance.setVersion()＆＃34;

进行新的更新，然后将数据库版本更新为新版本

if(yourDatabaseInstance.getVersion() < newDatabaseVersion)
{
      //create upgrades needed between the two versions "oldVersion" to "newVersion"
      yourDatabaseInstance.setVersion(newDatabaseVersion);
}

Answer 2

我用自己的方式解决了！只需在createDatabase方法中添加一些代码。

public void createDataBase() throws IOException {

    boolean mDataBaseExist = checkDataBase();
    if (!mDataBaseExist) {

        this.getReadableDatabase();
        this.close();
        try {
            copyDataBase();
        } catch (IOException mIOException) {
            throw new Error("ErrorCopyingDataBase");
        }
        }
    else{
        SQLiteDatabase db = getReadableDatabase();
        if(db.getVersion()<DATABASE_VERSION){
        this.getReadableDatabase();
        this.close();
        try {
            copyDataBase();
        } catch (IOException mIOException) {
            throw new Error("ErrorCopyingDataBase");
        }
        }
    }

}

毕竟，我认为升级的最佳方式是更改数据库名称..

Android为现有数据库升级数据库的最简单方法是什么

2 个答案: