I am trying to use rawQuery and execSQL methods for manipulating my database, instead of the .update, .insert, etc. I am trying to perform an UPDATE with the following code:

db.execSQL("UPDATE configuration " +
                "SET number_fields = " + number_fields + ", "
                + "frequency = " + frequency + ", "
                + "ag = " + ag + ", "
                + "number_alarms = " + number_alarms + ", "
                + "failed_rapper = " + failed_rapper + ", "
                + "max_mv = " + max_mv + ", "
                + "max_nav = " + max_nav + " "
                + "WHERE serial_id = " + Integer.toString(id) + ";");

在此操作之后，有一个日志表明发生了更新并且它似乎可以工作，但是当我尝试在表上执行 select 语句时，它返回并显示以下错误:

AFter this action there is a log that states an update has occurred and it seems to work, yet when I try to do a select statement on the table, it returns with the following error:

06-10 10:01:47.564: W/System.err(3815): android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0

现在，我在 Android 中使用 SQLite 数据库浏览器手动插入的不同数据上执行了相同的 SELECT，它工作正常.我还在 SQLite 浏览器中执行了相同的 UPADTE，它在那里工作.因此，我知道问题在于 UPDATE 命令在 Android 上运行时不起作用.

Now I have performed that same SELECT on different data in Android that I manually inserted using SQLite Database Browser and it works fine. I have also performed that same UPADTE in the SQLite Browser and it has worked there. Therefore I know that the problem is that the UPDATE command is not working when running on Android.

问题:为什么 UPDATE 命令在 execSQL() 方法中不起作用?

Question: Why does the UPDATE command not work within the execSQL() method?

推荐答案

来自Android SQLiteDatabase 类文档:

执行不是 SELECT 或任何其他 SQL 的单个 SQL 语句返回数据的语句.

Execute a single SQL statement that is NOT a SELECT or any other SQL statement that returns data.

没有办法返回任何数据(比如受影响的人数行).相反，我们鼓励您使用 insert(String, String,内容值)，更新(字符串，内容值，字符串，字符串 [])等al，如果可能的话.

It has no means to return any data (such as the number of affected rows). Instead, you're encouraged to use insert(String, String, ContentValues), update(String, ContentValues, String, String[]), et al, when possible.

然后:

对于 UPDATE 语句，请改用以下任何一种.

For UPDATE statements, use any of the following instead.

更新(字符串，内容值，字符串，字符串[])

update(String, ContentValues, String, String[])

updateWithOnConflict(String, ContentValues, String, String[], int)

updateWithOnConflict(String, ContentValues, String, String[], int)