Re: Solved, and a bug found! Re: JDBC question: Creating new - Mailing list pgsql-general

From Ed Yu
Subject Re: Solved, and a bug found! Re: JDBC question: Creating new
Date
Msg-id ZEgB9.61679$ku2.4393734@twister.southeast.rr.com
Whole thread Raw
In response to Solved, and a bug found! Re: JDBC question: Creating new arrays  (Joe Tomcat <tomcat@mobile.mp>)
List pgsql-general
Actually storing an array in an RDBMS table column is a feature in
Postgresql that does not exists in most other database. So, in other words,
it is not driver-independence, it is database dependent.

"Joe Tomcat" <tomcat@mobile.mp> wrote in message
news:1037239808.1318.466.camel@linux...
> On Tue, 2002-11-12 at 17:39, Doug McNaught wrote:
> > Then you probably need to wrap your Java array in an object that
> > implements java.sql.Array so that the JDBC driver can talk to it.
> > Shouldn't be hard.
>
> That still doesn't make it driver-independent, does it?
>
> Anyway, I found a simple solution that works easily with Postgres: The
> way PreparedStatement.setArray(Array) works is that it actually gets
> translated to PreparedStatement.setString(Array.toString()).  The
> Array.toString() method is very simple; it just makes a string that
> looks like '{484,282,945}' (for an int[]) so I just turned my int[] into
> such a string, and called PreparedStatement.setString().  This is a bit
> of a hack, but it seems that there is no db-independent way to do this,
> so I have no other options.  If we need to move to some other db, this
> shouldn't be hard to modify as needed.
>
> There is one other problem, though:  If I have an array with no
> elements, then this operation:
>
> Array array = resultSet.getArray(3);
> Object o = array.getArray();
>
> throws a Bad Integer exception.  This seems like it must be a bug in the
> JDBC.  To get around it, I put the o = array.getArray() inside a try
> block, and if throws an exception, I know that the array is
> zero-length.  This is clunky and it violates the principle of "Only use
> exceptions for exceptional conditions" and probably has some performance
> problems.  It seems that array.getArray() should always be able to
> return properly because that should be a class invariant.
>
> Any suggestions on this?
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
>     (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)



pgsql-general by date:

Previous
From: "Lee Crampton"
Date:
Subject: Re: Error in SELECT clause with UPPER function
Next
From: John Burski
Date:
Subject: Re: Parse error