Question

我编辑了设备名称，我想将编辑后的值保存到数据库，但是没有保存。

String strSQL = "UPDATE DeviceDetails SET devicename ='"+ edittext.getText().toString() +"'  WHERE uuid = '"+c.getString(c.getColumnIndex("uuid"))+"'" ;
db.select(strSQL);

以下是我的数据库适配器。在此我执行查询并保存到数据库，但事实并非如此。

                   public class DataBaseAdapter {

 public static final String KEY_ROWID = "_id";

    public static final String UUID = "uuid";
    public static final String DEVICENAME = "devicename";
    public static final String LIGHT = "light";
    public static final String ALARM ="alarm";


    private static final String TAG = "DDAdapter";

    private static final String DATABASE_NAME = "DeviceAdapter.db";
    private static final String DATABASE_TABLE = "DeviceDetails";
    private static final int DATABASE_VERSION = 3;

   private static final String DATABASE_CREATE =
       "create table DeviceDetails (uuid varchar(50) primary key  , " +
                                    "devicename varchar(50) ,light varchar(50),alarm varchar(50));";



    private final Context context;    

    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    public DataBaseAdapter(Context ctx) 
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

    private static class DatabaseHelper extends SQLiteOpenHelper 
    {
        DatabaseHelper(Context context) 
        {
            super(context, DATABASE_NAME,null, DATABASE_VERSION);

        }



        @Override
        public void onCreate(SQLiteDatabase db) 
        {
            try {
            db.execSQL(DATABASE_CREATE);
           } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");


            Log.i("i am in onUpgrade", ""+db);

            db.execSQL("DROP TABLE IF EXISTS DeviceDetails");
            onCreate(db);
        }
    }    

    public DataBaseAdapter open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }


    public void close() 
    {
        DBHelper.close();
    }

    public long insertData(String uuid,String devicename ,String light,String alarm ) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(UUID, uuid);
        initialValues.put(DEVICENAME, devicename);
        initialValues.put(LIGHT, light);
        initialValues.put(ALARM, alarm);
        return db.insert(DATABASE_TABLE, null, initialValues);
    }




public Cursor getData(){
        return db.query(DATABASE_TABLE, new String[] {UUID,DEVICENAME,LIGHT,ALARM,
                }, null, null, null, null, null);
    }

  public Cursor select(String query) throws SQLException {
        return db.rawQuery(query, null);
    }

/* public void select(String query) throws SQLException {
         db.execSQL(query, null);
    }*/
  public long updateName( String newName) {
        ContentValues values = new ContentValues();
        values.put(DEVICENAME, newName);
        return db.replace(DATABASE_TABLE, null, values);
        //(DATABASE_TABLE, values, DEVICENAME + " = '" + newName + "", null);
    }  
}

Answer 1

e.g. you want to update the DEVICENAME where UUID is _uuid.
Then use like

public long updateName( String newName, String _uuid) 
{
   ContentValues values = new ContentValues();
   values.put(DEVICENAME, newName);
   return db.update(DATABASE_TABLE, values,UUID + "= ?",new String[] { uuid});
}

Answer 2

String strSQL = "UPDATE DeviceDetails SET devicename ='"+ edittext.getText().toString() +"'  WHERE uuid = '"+c.getString(c.getColumnIndex("uuid"))+"'" ;
db.rawQuery(strSQL);

试试这个

Answer 3

您有两个选择

1）execSQL：

 ...
 String strSQL = "UPDATE DeviceDetails SET devicename ='"+ 
                 edittext.getText().toString() +
                 "'  WHERE uuid = '"+
                 c.getString(c.getColumnIndex("uuid"))+"'" ;
 db.execSQL(String sql)
 ...

或者2）你可以使用update :(参见@ajit代码以获得更合适的例子，他更好地使用UUID）

public long updateName(String newName, String uuid) {
    ContentValues values = new ContentValues();
    values.put(UUID, uuid);
    values.put(DEVICENAME, newName);
    return db.update(DATABASE_TABLE, values, KEY_ROWID + "=" + rowId, null);
    //(DATABASE_TABLE, values, DEVICENAME + " = '" + newName + "", null);
}

Answer 4

类似于insert db，而不是db.insert（），我们必须使用db.update（），如下所示，

  ContentValues initialValues = new ContentValues();
    //update column where u want to update for example,

    initialValues.put(DEVICENAME, devicename);
   db.update((DATABASE_TABLE, initialValues ,UUID+" = "+ uuid+ "", null);

如何将重命名值保存到数据库？

4 个答案: