Question

下面是我的数据库代码，我试图通过更改版本号来升级它当我运行表时，不会重新创建或更改...代码中的任何错误都可以帮助

public class DBHelper extends SQLiteOpenHelper {
    public static final int db_version = 1;
    private static final String CL_CITY = null;
    public static final String COL_NAME = "pName";
    //private static final String TABLE_NAME = CL_CITY;
    public static String TAG = DBHelper.class.getName();
    public static String DB_PATH = "data/data/org.clock/database/";
    private static String STATUS= "STATUS";
    private static String dbName = "clock.db";
    private static final String STRING_ALTER = "ALTER TABLE "+CL_CITY+" ADD "+STATUS+" STATUS";


    protected SQLiteDatabase dataBase;
    protected Context context;
    //private Context context;
    private static SQLiteDatabase checkDB = null;
    public DBHelper(Context context, String dbName) {
        super(context, dbName, null, 34);
        //this.dbName = dbName;
        this.context = context;
    }

    public void createDb() throws IOException {
        boolean dbExist = checkDataBase();
        Log.d(TAG, "DBChecking............ dbExist : " + dbExist);
        if (!dbExist) {
            this.getReadableDatabase();
            try {
                copyDataBase();
            } catch (IOException e) {
                Log.d(TAG, "Error cloneing database" + e);
            }
        }
    }

    private boolean checkDataBase() {

        try {
            if(checkDB == null){
                String path = DB_PATH + dbName;
                Log.d(TAG, "checkDataBase path=" + path);
                checkDB = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
            }
        } catch (SQLiteException e) {
            Log.e(TAG, "DBChecking............ ", e);
        }
        /*if (checkDB != null) {
            checkDB.close();
        }*/
        return checkDB != null ? true : false;
    }

    private void copyDataBase() throws IOException {
        Log.i(TAG, "copyDataBase database...");
        File file = new File(DB_PATH);
        Log.i(TAG, "cloneDataBase file=" + file);
        file.mkdirs();
        InputStream dbInput = context.getAssets().open(dbName);
        String outPutFile = DB_PATH + dbName;
        Log.i(TAG, "copyDataBase outPutFile=" + outPutFile);
        OutputStream dbOutPut = new FileOutputStream(outPutFile);
        byte[] buffer = new byte[1024];
        Log.i(TAG, "copyDataBase buffer=" + buffer);
        int length;
        while ((length = dbInput.read(buffer)) > 0) {
            dbOutPut.write(buffer, 0, length);
        }
        dbOutPut.flush();
        dbOutPut.close();
        dbInput.close();
    }

    public void openDb() throws SQLException {
        String dbPath = DB_PATH + dbName;
        dataBase = SQLiteDatabase.openDatabase(dbPath, null,
                SQLiteDatabase.OPEN_READWRITE);
    }

    @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) {

if (newVersion > oldVersion){

    //db.execSQL("CREATE TABLE "+"staff"+" (_id INTEGER PRIMARY KEY AUTOINCREMENT, "
          // +COL_NAME+" TEXT);");

           db.execSQL("STRING_ALTER ");

    }
    }}

Answer 1

将db.execSQL("STRING_ALTER ");更改为db.execSQL(STRING_ALTER);

另请检查您的alter sql命令。看起来很不对劲。

Answer 2

我注意到您使用的是错误的数据库路径：

public static String DB_PATH = "data/data/org.clock/database/";

这应该是：

public static String DB_PATH = "data/data/org.clock/databases/";

（database / ==＆gt; databases /）

无法升级数据库

2 个答案: