Check if Record Exists in database

Question

I am trying to check if a record exists after selecting it using a query. I have one record in the table which is 'Administrator' 'abc123' and I am trying to use the following code below:

     //Define our database variables that we will use to get our data.
    dbhelper = new DBHelper(this);
    SQLiteDatabase db = dbhelper.getReadableDatabase();

    //Define our select query here, check if username and password exists.
    String selectQuery = "SELECT * FROM " + dbTables.userTABLE +
            " WHERE " + dbTables.username +
            " = " + "'" + input_name + "'" + " AND " +
            dbTables.userpassword + " = " + "'" + input_password + "'";

    Cursor c = db.rawQuery(selectQuery, null);

    //If the raw query was successfull.
    if(c.moveToFirst()){

        Integer userID = c.getInt(0);
        String userName = c.getString(1);
        String userPassword = c.getString(2);

        boolean exists = (c.getCount() > 0);

        if( exists )
        {
            Log.d("Database", userID.toString());
            Log.d("Database", userName.toString());
            Log.d("Database", userPassword.toString());
        }
        else
        {
            Log.d("Database NO", "NO");
        }

    }

    c.close();
    db.close();

This works when the record exists however when the record doesn't exist it doesn't print anything at all. I have tried entering a different username and password that doesn't exist in the database and it doesn't seem to print anything. What am I doing wrong?

One don't select *. It will move all columns to the buffer. select only one column. 2nd don't invent your own security. Ping a service to authenticate. — danny117
– danny117, Commented Apr 3, 2017 at 14:18
This doesn't relate to your question, but use prepared statements! Your code is susceptible to SQL-injection attacks. — RichN
– RichN, Commented Apr 3, 2017 at 20:41

azizbekian · Accepted Answer · 2017-04-03 14:14:27Z

3

From docs:

Return boolean, indicating whether the move succeeded.

if (c.moveToFirst()) {
  ...
} else {
    // cursor is empty, print here
}

Obviously, if there are no records then move hasn't succeeded, you have to check it in else block.

answered Apr 3, 2017 at 14:14

azizbekian

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