With out using resultset..?

[santhosh.R gowda]

Dear all

Is is possible to know where the record exists in DataBase for a preticular condition with out using Result set object
For Ex:- iwant to check the userid in database so that i will check in database and using result set i will forward my logic .

[Jan Cumps]

ResultSet is the interface to retrieve answers from your database.
Is there a reason why you can't use it for this purpose?

[Tim Holloway]

Santhosh, you might want to get someone to help you to phrase that question a little more understandably.

I think what you're trying to do is the common case where you want to see if a user is defined in a database, but you do not actually want to retrieve any of the user data. The SQL version of that would be:

SELECT COUNT(*) FROM USER WHERE USER_ID = ?

Or, if you're doing a login check:

SELECT COUNT(*) FROM USER WHERE USER_ID = ? AND PASSWORD = ?

These queries do return a result set, but it has only one row and one column, and its value is either 1 (user exists, password valid) or 0 (user does not exist, or password is invalid).

So, while you need a ResultSet, the logic isn't all that complicated and the overhead is pretty low:

ResultSet rs = statemen.executeQuery();
if ( ! rs.next() ) {
  // DATABASE ERROR!
  throw new DatabaseException("Could not check user");
}
int userCount = rs.getInt(1);
if ( userCount = 0 ) {
  throw new LoginFailException();
}
// Otherwise user ID/password is OK

This code won't execute - I've done some simplifications to illustrate the concept, but it's basically how you'd do something like that.