Android SQLite数据库在更新多个更新时未更新

Question

我正在尝试更新Android中的sql数据库。

public boolean updatepasswordbySimcardnumber(String simcard, String password) { 
      mDbHelper = new DatabaseHelper(mCtx); 
      mDb = mDbHelper.getWritableDatabase();   
     Cursor mCursor = null; 
     int retvalue = 0; 

     mCursor = mDb.query(SQLITE_TABLE, new String[] {KEY_ROWID, 
        KEY_IDNUM, KEY_SIMCARD, KEY_DESCRIPTION, KEY_MODEL, KEY_TIMEINSTANCE, KEY_PASSWORD}, 
        null, null, null, null, null); 

     for(mCursor.moveToFirst(); !mCursor.isAfterLast(); mCursor.moveToNext()){ 
      if(mCursor.getString(2).equals(simcard)){ 
        ContentValues updatevalue = new ContentValues();   
        updatevalue.put(KEY_PASSWORD, password);    
        long colId = mCursor.getColumnIndex(KEY_ROWID); 
        retvalue = mDb.update(SQLITE_TABLE, updatevalue, KEY_ROWID + "=?",new String[] { String.valueOf(colId) });// + colId, null); 
        break; 
      } 
     } 
     mDbHelper.close(); 
     return retvalue > 0; 
    } 

但密码从未更新。 retvalue总是0.什么可能是错误的？ 感谢

Answer 1

而不是

long colId = mCursor.getColumnIndex(KEY_ROWID); 

应该

long colId = mCursor.getLong(getColumnIndex(KEY_ROWID)); 

Answer 2

其实你做错了。如果您有多个要插入数据库的记录，则必须设置开始事务。

您可以使用数据库事务这一点。

你怎么能在Android中使用数据库事务

If you want to start the transaction there is a method beginTransaction() 
If you want to commit the transaction there is a method setTransactionSuccessful() which will commit the values in the database 
If you had start the transaction you need to close the transaction so there is a method endTransaction() which will end your database transaction 

现在有两个要点

If you want to set transaction successful you need to write setTransactionSuccessful() and then endTransaction() after beginTransaction() 
If you want to rollback your transaction then you need to endTransaction() without committing the transaction by setTransactionSuccessful(). 

编辑：

EX：

db.beginTransaction(); 
     try { 
      // update table 
      db.setTransactionSuccessful(); 

     }catch { 
      //Error in between database transaction 
     }finally { 
       db.endTransaction(); 

     }