Hashtable- how to retrieve key for a particular value?

Question

I fetched few values from the database and stored all them using hashtable. Then i check for the value entered by the user in a textbox using contains() method of hashtable. Now i want to fetch the key associated to this particular value so that i can pass it to my rest of the program?
Pls help me....

Answer 1

The obvious question is what are you using as your key when you store the value into your hashtable?? The idea behind the key/value system is that you use the key to get the value you want, not the other way around. In your current situation, the contains() method might return true, but that could you mean you have 1, or 1000 instances of that value in your hashtable. Which key do you want? You could, I suppose, parse through the output of Hashtable.toString()... but that still wouldn't resolve the possibility of duplicate values in the hash.
Another possible solution to your problem, depending on how your application works, is to wait until you get that user input before running your database query. Simply append the added info onto your SQL SELECT statement to accurate retrieve only those entries from the database that you will need.