Question

Assume that I get a Cursor by db.query().
Then I modify a field in a row by db.update(),and this row is included by Cursor queried before.
Data in this Cursor will change or not?

like this:

Cursor cur = db.query("[some parameter can get row 0]"); 
cur.moveToFirst; 
int a = cur.getInt(0);
db.update("[some parameter can modify row 0 col 0]");
int b = cur.getInt(0);

Is (a==b) true or false ?

====== edited 2012.10.1 =========
I am not a pro-programmer,and too busy to code in these days.
If I make you unhappy ,I am very sorry.
Finally , I get a holiday of a week, haha .

I do some coding like this:

SQLiteOpenHelper h = null;
SQLiteDatabase db = null;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    h=new SQLiteOpenHelper(this, "test.db", null,1){

        @Override
        public void onCreate(SQLiteDatabase arg0) {
            // TODO Auto-generated method stub
            arg0.execSQL("CREATE TABLE t1 (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT )");
            arg0.execSQL("INSERT INTO t1 (name) VALUES ('name_wrong')");
        }

        @Override
        public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
            // TODO Auto-generated method stub

        }};

    db=h.getWritableDatabase();
    Cursor cur =  db.query("t1", null, null, null, null, null, null);
    cur.moveToFirst();
    String s1=cur.getString(1);

    db.execSQL("UPDATE t1 SET name = 'name_right'");

    String s2=cur.getString(1);
    Log.d("","s1 = "+s1);
    Log.d("","s2 = "+s2);
    Log.d("","s1 == s2 is "+s1.equals(s2));
    Log.d("","requery...");
    cur =  db.query("t1", null, null, null, null, null, null);
    cur.moveToFirst();
    s2=cur.getString(1);
    Log.d("","s1 = "+s1);
    Log.d("","s2 = "+s2);
    Log.d("","s1 == s2 is "+s1.equals(s2));
}  

And logcat say that:

10-01 03:11:28.356: D/(1514): s1 = name_wrong
10-01 03:11:28.356: D/(1514): s2 = name_wrong
10-01 03:11:28.356: D/(1514): s1 == s2 is true
10-01 03:11:28.356: D/(1514): requery...
10-01 03:11:28.356: D/(1514): s1 = name_wrong
10-01 03:11:28.356: D/(1514): s2 = name_right
10-01 03:11:28.356: D/(1514): s1 == s2 is false

So I think I get the answer
Thank you all guys.

Answer 1

1. you don’t see any changes except if you re-query.
2. cursors are not live. that is, the moment you have a cursor loaded, it has nothing to do with the database anymore. it is just a data structure (like an array).

Basically

Is (a==b) true or false ?

false