September 2012

After the success of the last Oracle/SQL Server discussion, James Murtagh of Redgate has arranged another online discussion – this time about the different ways in which temporary tables are implemented and used. As before I’ll be doing the Oracle bit and Grant Fritchey will be doing the SQL Server bit.

Update: Now that the event is over, you can listen to the recording at this URL.

WordPress 3.4.2 has been released. You can see the bug fixes in the changelog and download from the usual place.

Happy upgrading.

Cheers

Tim…

Here’s a (camouflaged) constraint definition I came across a little while ago in a production system:

create table t1 (
	v1 varchar2(10),
	constraint c1 check (v1 = 'A' or v1 = null)
);

Quick question – will the following insert statement work or return an error ?

insert into t1 values('B');

The answer is that the row gets inserted – and that’s probably not an intended result.

It’s amazing how often NULL rears its ugly head as the cause of unexpected behaviour. Remember that a constraint accepts a value if the constraint does not evaluate to false. If you put ‘B’ into the constraint definition above, we get:

       'B' = 'A' or 'B' = null
hence   FALSE or NULL
hence   NULL

OK, its not Oracle database security but its big news and it is from Oracle. Oracle have recently released an out of band Java security patch which supposedly fixed serious security flaws; then a few days ago the guys at....[Read More]

Posted by Pete On 05/09/12 At 12:11 PM