Hello,
Does it make sense if i design a table with 2 columns with out defining any key?
username varchar(64) notnull and password varchar(64) notnull
This table does'nt have relation with any other table, shld we really have an id field???
lets say if i compare the username and password entered by the user against the values stored in the table by using the following prepared statements, will it have any disadvantages??

pstmt = connection.prepareStatement("select * from TBL_NAME where username='"+Uname.getText()+"' and password = '"+new MD5().getHash(Passwd.getText())+"';");
rset = pstmt.executeQuery();

As of now everything works fine, but i'd like to know if its a good design.

Thanks for your time

you need a key to keep the entries unique. If the key is missing you can use one username and one password several times...

You should have a primary key defined so that (at the minimum)
you have a means of quickly SELECTing from your records.
A primary key automatically creates an index for you. This index
will become very important when your database gets large.

That said, there's no important reason why you need a separate
ID field. Your username field would make a good primary key field if you
want usernames to be unique. If usernames don't have to be unique,
then you could make a compound primary
key using both username and password.

Thanks for your responses.