Android的SQLite的：如何知道删除行之前的数据存在 [英] Android SQLite: How to know data exist before deleting row

问题描述

试图删除使用查询通过ID表内的一行。假设ID不存在，那么如何知道ID或行信息不存在？

code如下：

 公共无效deletePerson的（字符串PERSONID）{
        SQLiteDatabase SQLDB = getWritableDatabase（）;
        sqldb.execSQL（DELETE FROM+ TABLE_NAME +WHERE+ COLUMN_NAME +='+ PERSONID +'）;
        Toast.makeText（背景下，记录removedId，Toast.LENGTH_SHORT）.show（）;
    }
 

解决方案

您不一定需要知道，DELETE不会失败，如果没有记录符合标准的地方。

Trying to deleting a row inside a table using query by id. Suppose that id not exists, then how to know that id or row info not exists?

code below:

public void deletePerson(String personId){
        SQLiteDatabase sqldb = getWritableDatabase();
        sqldb.execSQL("DELETE FROM " + TABLE_NAME + " WHERE " + COLUMN_NAME + " = '" + personId+"'");
        Toast.makeText(context,"Record removedId", Toast.LENGTH_SHORT).show();
    }

解决方案

You don't necessarily need to know, DELETE won't fail if there is no record that meets the where criteria.

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