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From Michael Segel <mse...@segel.com>
Subject Re: No current connection
Date Fri, 03 Mar 2006 14:46:24 GMT
On Friday 03 March 2006 7:58 am, Rhys Campbell wrote:
> Hi,
>
> I have a method called initDatabase() which returns the Connection
> variable. When I execute any query against the database I call another
> method of which the first parameter is the Connection (i.e. I place
> initDatabase() as the parameter.
>
> i.e. ResultSet rs = database.executeQuery(initDatabase(), "SELECT * FROM
> myTable"); (Code from memory!)
>
>
Eeewww.

Uhm... initDatabase() is a method within your current class. Ok...
By the name of the function, you're implying that you're opening up a data 
connection each time initDatabase is called....

Lots of overhead that could be adverted if you change the scope of the 
instance of the Connection object.


> Connections are not passed between the main (business logic) classes.
> They all have access to a little class called DBTools which I wrote to
> simplify DB access.
>
> I have a play with your ideas this evening and maybe post my code.
> Thanks for your thoughts.
>
> Regards,
>
> Rhys
>
> -----Original Message-----
> From: Michael Segel [mailto:msegel@segel.com]
> Sent: 03 March 2006 13:36
> To: Rhys Campbell
> Subject: Re: No current connection
>
> On Thursday 02 March 2006 7:20 pm, you wrote:
> > Hi,
> >
> > I'm using Derby for a current project for the first time. Got on with
>
> it
>
> > pretty well until tonight.
> >
> > My app starts up a database, drops a few views and then recreates
>
> them.
>
> > When another one of my Java classes moves on to do a small SELECT
>
> (that
>
> > should yield a single result). The exception "No current connection"
>
> is
>
> > raised with the query obviously failing.
> >
> > I have checked the Derby.log but I am warned that the file is binary,
>
> when
>
> > it opens in my editor, and a load of "junk" is displayed. I did use a
> > little tool called "fd" which is a oct / hex character editor. This
>
> did
>
> > make some sections of text legible but I couldn't see anything useful
>
> to
>
> > explain my issue.
> >
> > Can anyone offer me any pointers?
> >
> > Many thanks,
> >
> > Rhys
>
> Just to update the post I made...
>
> Since you mention multiple classes...
>
> 1) Check the scope of the connection declaration and are you passing it
> in as
> a parameter of your new class when you instantiate it?
>
> 2) Are you overwritting your connection in your new class, losing the
> connection for that instance of the class variable?
>
> Again, just shooting from the hip.

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