Re: Nest SQL queries and result sets?

From:

IchBin <weconsul@ptd.net>

Newsgroups:

comp.lang.java.help

Date:

Mon, 31 Jul 2006 15:41:21 -0400

Message-ID:

<B4Kdnb2Bmqx9wVPZUSdV9g@ptd.net>

Mo wrote:

I've tried both ways and doesn't seem to matter.

Wojtek Bok wrote:

Mo wrote:

I'm trying to use a while loop to loop through a result set, and inside
that results set call another query. Like....

database_conn1 = new DBConnection(url, user, pass);
database_conn2 = new DBConnection(url, user, pass);

ResultSet records_conn1 = database_conn1.executeQuery(sqlstatment01);

while (records_conn1.next()) {

          records1_conn.getString(1);

          ResultSet records_conn2 =
database_conn2.executeQuery(sqlstatment02);

          while (records_conn2.next()) {
                  records2_conn.getString(1);
          }

}

(I have try and catch around the while statements, just trying to keep
the code simple)

What happens is the outside result set gets the first record, the
inside record gets all of it's results and then it gives me a null
pointer exception. I'm not sure if it is because the inside result set
closes down everything or what. Is this even possible, or is there a
better way to do this?

I have had problems where I am not retrieving (getxx(1) the columns in
the exact order they were specified in the select statement. This is
especially important where you are retrieving a TEXT type.

I always use columns names, rather than index numbers as this assures
that I an getting what I think I am getting. So getxxx("columnName").

Could you just un-nest your two connects\querys and run them in
sequentially in separate sequences. That is, run your first query and
load the results into an array. Once all data is retrieved on the first
query perform a loop against the second database looping on the array
from the first db connection.

Thanks in Advance...
IchBin, Pocono Lake, Pa, USA http://weconsultants.phpnet.us
__________________________________________________________________________

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