Help In JDBC

[juhiswt]

I am making a program to search the student detail by enterering the roll number.In this I want to do if the student of entered roll number doest not exist in databse then it should diaplay a dialogue box The student of that roll number does not exist.
I have used
if(rs.wasNull())
display the dialogue box
else
display the details
but in each case else is executing but if is not why it is?

[Bigfatcat]

Could you post the code relating to the assignment of the rs (ResultSet I assume)?

No need for the whole code block, just the bits relating to 'rs'.

[juhiswt]

Yes its result set

[juhiswt]

while(res.next())
{
String name=res.getString(1);
String city=res.getString(2);
String class1=res.getString(3);
if(res.wasNull())
{

tf1.setText("Does nOt EXist");
tf2.setText("Does nOt EXist");
tf3.setText("Does nOt EXist");
}
else
{
tf1.setText(name);
tf2.setText(city);
tf3.setText(class1);
}

}

[JosAH]

Read the API documentation for the ResultSet.wasNull() method; it doesn't do what you hope it does; hint, if there is no ResultSet.next() element no student matched the criteria ...

kind regards,

Jos

[juhiswt]

@JosAH could u please tell me what should i use and i have read wasNull method but i can not get its use could u please tell me this also..
Thanx

[JosAH]

@JosAH could u please tell me what should i use and i have read wasNull method but i can not get its use could u please tell me this also..
Thanx

If no row exists in the database for the given sql query, there doesn't exist a ResultSet.next() (i.e. that method returns false after the first call) so your while loop body is never entered; you should display your notification in that case.

kind regards,

Jos

[juhiswt]

@JosAH thanx alot ...

[RichersooN]

I think your problem is quite similar to my problem:

http://www.java-forums.org/database/...return-same-i-
need-refresh.html

There is bug on resultset

[JosAH]

I think your problem is quite similar to my problem:

http://www.java-forums.org/database/...return-same-i-
need-refresh.html

There is bug on resultset

Have you read this thread? What the OP described most certainly wasn't a bug on the ResultSet part. b.t.w. the bugbase is full of bugs that aren't bugs ...

kind regards,

Jos