本文介绍了Android 为现有数据库升级数据库的简单方法是什么的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

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..

这篇关于Android 为现有数据库升级数据库的简单方法是什么的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

08-26 08:52
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