Android 为现有数据库升级数据库的简单方法是什么

问题描述

我有一个应用程序，它有数据库，发布后.我已将一些表添加到我的数据库中.

I hava app, and it has database, after published. I have add some tables to the my database.

当客户在市场上更新此应用程序时，我如何可以轻松地使用已安装手机的旧数据库更新新数据库.

How can I easily update new database with old database which was already installed phone before when a customer update this application on market.

这是我的代码.onUpgrade应该写什么?

Here is my Code. What should I write in onUpgrade?

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) {

        }}

推荐答案

我已经用我的方法解决了！只需在 createDatabase 方法中添加一些代码.

Well I have solved with my way! just adding some codes in to createDatabase method.

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法是更改数据库名称..

After all, I think best way is for upgrade is changing the database name..

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