You’re On A Roll(back)

"I know one thing for certain; it is much harder to tell whether you are lost than whether 
you were lost, for, on many occasions, where you are going is exactly where you are. On 
the other hand, if you often find that where you've been is not at all where you should have 
gone, and, since it's much more difficult to find your way back from someplace you've never 
left, I suggest you go  (more...)

Results, What Results?

"For instance," said the boy again, "if Christmas trees were people and people were Christmas trees,
we'd all be chopped down, put up in the living room, and covered in tinsel, while the trees opened our presents."
"What does that have to do with it?" asked Milo.
"Nothing at all," he answered, "but it's an interesting possibility, don't you think?"
Norton Juster, The Phantom Tollbooth 

Oracle offers a results cache in the (more...)

Hakan You Do That?

"Everyone understands numbers. No matter what language you speak,
they always mean the same thing. A seven is a seven anywhere in the world." 
Norton Juster, The Phantom Tollbooth 

An interesting problem submitted to Oracle Support involves a possibly little-known aspect of a table called the Hakan Factor. The problem description, in brief, states that the Hakan Factor isn’t preserved for a partitioned table when a single partition is compressed. Why is this a (more...)

You’re Not Allowed

"Have you ever heard a blindfolded octopus unwrap a cellophane-covered bathtub?"
Norton Juster, The Phantom Tollbooth 

Recently a thread in an Oracle forum I frequent asked the following question:

“… is there a way to restrict the login to database only from the application which we have made.”

That, of course, is not an easy question to answer as several possibilities emerge with none of them foolproof. Let’s look at those options.

The (more...)

“But, You Don’t Understand…”

"Let me try once more," he said in an effort to explain. "In other words--"

"You mean you have other words?" cried the bird happily. "Well, by all means, use them.
You're certainly not doing very well with the ones you have now."
- Norton Juster, The Phantom Tollbooth 

A seemingly constant battle in many forums is getting those who post questions to be clear in what they are asking. Some questions are (more...)

What’s In A (User) Name?

"So each one of you agrees to disagree with whatever the other one agrees with,
but if you both disagree with the same thing, aren't you really in agreement?"
- Norton Juster, The Phantom Tollbooth

Recently a blog post caught my attention, primarily because it was talking about primary keys in a database. In the post an interesting situatino was presented, one involving using a username column as the key. The point was made (more...)

It Isn’t The Index

"If you want sense, you'll have to make it yourself."
- Norton Juster, The Phantom Tollbooth

One of the more confusing statistics in Oracle is, apparently, one called the clustering factor. Associated with an index (as evidenced by the columns in DBA_INDEXES) it’s actually dependent on the table data, more specifically the distance between ‘jumps’ for a given index key. Let’s define a ‘jump’ to be the number of blocks between rows containing the (more...)

Let Me Say That Another Way …

"I never knew words could be so confusing," Milo said to Tock as he bent down to scratch the dog's ear.
"Only when you use a lot to say a little," answered Tock.  Milo thought this was quite the wisest thing he'd heard all day.
-- Norton Juster, The Phantom Tollbooth

Occasionally it may be necessary to ‘flip’ a table on its side, so to speak, meaning to convert rows to columns in order to (more...)

Stop That!

"It seems to me that almost everything is a waste of time."
- Norton Juster, The Phantom Tollbooth 

Jonathan Lewis has coined a term and its definition that, I believe, we’ll be using quite a bit:

Stoptimisation - the art of optimisation by not doing the things you don't need to do.

It’s a term we’ve needed for some time now, given the pendulum swing back to the days of yore (meaning pre-9i) with (more...)

That Depends

In every universe there are questions that either:

Have no answer
Have an answer that is situation-dependent

and that includes the Oracle universe. Sometimes it’s difficult to get that concept across to the less knowledgeable. Let’s go back to a simple example from a previous post to illustrate this.

In Resurrecting The Dead flashback operations were discussed as an option to restore table data to before an errant update. The post started with this: