Thursday, November 12, 2009

Data Modeling

Most readers of the blog are probably DBA's, or do DBA work along with development or other duties.

Though my title is DBA, Data Modeling is something I really like to do.

When first learning Oracle, I cut my teeth on data modeling, and used CASE 5.1 on unix to model a database system. True, CASE 5.0 used an Oracle Forms 3.x based interface, and the GUI modeling was unix only.

That was alright with me, as the Form interface allowed manual changes to be made quite quickly.

And the graphic modeling tool was fairly decent, even on a PC running Hummingbird X Server.

When Designer 2000 came out, it was clearly a more capable tool. Not only did it do everything that CASE 5.1 could do, it could do more. I won't make any silly claim that I was ever able to fully exploit D2K, as it was an end-to-end tool that could do much more than model data and databases.

What it could do with just the databases however was quite good.  Data models could be created, and then a physical database could be generated from the model.

Changes in the database model could be reverse engineered back to the model, and changes in the model could be forward engineered in to the physical model. D2K could truly separate logical and physical models, and allow changes to be migrated back and forth between the two.

There are other high end tools such as Erwin which can no doubt accomplish the same thing, but I have not used them.  

One important differentiation for me between D2K and other tools was that D2K worked with Barker Notation, which is the notation I first learned, and the one I still prefer.  

I should not speak of Designer 2000 in past tense I guess, as it is still available from Oracle as part of the Oracle Development Suite, but is now called Oracle Designer.  It just hasn't received much attention in the past few years, as I think many people have come to think of data modeling as too much overhead.  

I've tried several low end tools in the past few years, and while some claim to separate logical and physical models, those that I have tried actually do a rather poor job of it.

All this leads to some new (at least, new to me) developments from of all places, Microsoft.

Maybe you have heard of Oslo, Microsoft's Data Modeling toolset that has been in development for the past couple years.

If you're just now hearing about it, you will likely be hearing much more. The bit I have read has made me think this will be a very impressive tool.

If you have done data modeling, you have likely used traditional tools that allow you to define entities, drop them on a graphical model, and define relationships.

The tool you used may even have allowed you to create domains that could be used to provide data consistency among the entities.

Oslo is different.  

Oslo incorporates a data definition language M. The definitions can be translated to T-SQL, which in turn can be used to create the physical aspects of the model.  M also allows easy creation of strongly typed data types which are carried over into the model.

Whether Oslo will allow round trip engineering ala D2K, I don't yet know.

I do however think this is a very innovative approach to modeling data. 

Here are a few Oslo related links to peruse :

You may be thinking that I have given SQL Developer Data Modeler short shrift.

Along with a lot of other folks, I eagerly anticipated the arrival of SQL Developer Data Modeler.

And along with many others, was disappointed to learn that this add on to SQL Developer would set us back a cool $3000 US per seat.  That seems a pretty steep price for tool that is nowhere near as capable as Oracle Designer, which is included as part of the Oracle Internet Developer Suite. True the price is nearly double that of SQL Modeler at $5800, but you get quite a bit more than just Designer with the Suite.

As for the cost of Oslo, it's probably too early to tell.

Some reading suggests that it will be included as part of SQL Server 2008, but it's probably too soon to tell.

Why all the talk about a SQL Server specific tool?

Because data modeling has been in a rut for quite some time, and Microsoft seems to have broken out of that rut.  It's time for Oracle to take notice and provide better tools for modeling, rather than upholding the status quo.

Monday, November 09, 2009

MetaLink, we barely knew ye

But, we wish we had more time to get better acquainted.

If you work with Oracle, you probably know that MetaLink went the way of the Dodo as part of an upgrade to My Oracle Support during the weekend of November 6th, 2009.

And so far it hasn't gone too well, as evidenced by these threads on Oracle-L:

Issues with My Oracle Support
Metalink Fiasco

Many people were lamenting the loss of MetaLink well before its demise, but I don't think any were quite expecting the issues that are currently appearing.

A few have reported that it is working fine for them, but personally, I have found  it unusable all morning.

At least one issue with MetaLink appears to have been cleared up with MOS, that is while I was able to login to it last week.

During a routine audit of who had access to our CSI numbers, I came across a group of consultants that were no longer working for our company, and froze their accounts.  The next day I received a frantic voice mail  from a member of the consulting firm, and he informed me that they had no access to MetaLink because I had frozen their accounts.

I returned the call just a few minutes later, but they had already been able to resolve the issue, as one of their consultants with admin rights had been unaffected, and was able to unfreeze their accounts.

Removing them from the CSI is the better procedure, but in the past when I have attempted to do so, I found that there were still open issues owned by the accounts, and could not remove them. The application owners had been very clear that this access should be removed, so I froze the accounts, so that is what I did on this occasion as well.

This all seemed quite bizarre to me.  This must be a very strange schema in the ML user database, and some strange logic to go along with it.  By granting a user access to a CSI, MetaLink was giving me Carte Blanche to effectively remove them from MetaLink.

How has My Oracle Support fixed this?  Try as I might, I could not find a 'freeze' button in user administration in MOS.  So the fix seems to have been "remove the button"