The Data Warrior

Changing the world, one data model at a time. How can I help you?

Archive for the tag “@thatjeffsmith”

#DataWarrior 2015 in review

Happy New Year again everybody!

Shoutout to Jeff Smith for again being the #1 real person that I actually know who referred people to my blog via his blog. If you don’t already, please add ThatJeffsSmith to your reading list.

The WordPress.com stats helper monkeys prepared a 2015 annual report for me.

Here’s an excerpt:

Madison Square Garden can seat 20,000 people for a concert. This blog was viewed about 69,000 times in 2015. If it were a concert at Madison Square Garden, it would take about 3 sold-out performances for that many people to see it.

Click here to see the complete report.

Cheers!

Kent

The Data Warrior and Snowflake Evangelist

Advertisements

Better Data Modeling: Discovering Foreign Keys (FK) in #SQLDevModeler (SDDM)

A while back I had an interesting situation when I was attempting to reverse engineer and document a database for a client.

I had a 3rd party database that had PKs defined on every table but no FKs in the database. The question I posed (on the Data Modeler Forum) was:

How do I get the FK Discover utility to find FK columns with this type of pattern:

Parent PK column = TABCUSTNUM

Child FK column = ABCCUSTNUM

So the root column name (CUSTNUM) is standard but in every table the column name has a different 3 character “prefix” that is effectively the table short name. Is there way to get the utility to ignore the first three characters of the column names?

This was in SDDM 4.1.873.

No easy answer.

Well, the ever helpful Philip was very kind and wrote me a slick custom Transformation Script that did the trick! (Check the post if you want to see the code.)

But wait there’s more!

In his response he mentioned a feature coming in 4.1.888 – the ability to include a table prefix as part of a FK column naming template (just like this app had done).

Cool, I thought, but how does that help?

Well with the template in place it turns out that you can have the FK Discovery utility search based on the Naming Template model rather than just look for exact matching column names.

Using the Custom Naming Template

So recently (today in fact) I was trying to add FKs to the Snowflake DB model I reverse engineered a few weeks back (Jeff pointed out they were missing). I noticed the model had that pattern of a prefix on both the FK and PK column names.

In the CUSTOMER table the PK is C_CUSTKEY. In the ORDER table it is O_CUSTKEY. Nice simple pattern (see the diagram below for more). That reminded me of the previous issue and Philip’s script.

Snowflake Schema

Off to OTN to find that discussion and refresh my memory.

In the post, Philip has posted an example of a template that fit my previous problem:

{table abbr}SUBSTR(4,30,FRONT,{ref column})

With the note that {table abbr} would be the equivalent of what I called the table prefix. So first I went to the table properties and put in the prefixes using the Abbreviation property:

Add Table Abbrev

Then all I had to do was modify his example to account for the underscore and the fact that the main column text would start at character #3 instead of #4:

{table abbr}_SUBSTR(3,30,FRONT,{ref column})

I input that by going to Properties -> Settings -> Naming Standards -> Templates and then editing the default template:

Set up FK template

Discover FKs!

Now it was just a matter of running the utility. You find that with a right mouse click on the Relational Design node:

Discover FK tool

Next you get the list of candidate FKs:

Create FKs

Note that the utility also suggested some FKs based on the unique constraints (UKs) as well. I did not want those, so I unchecked them before I hit “OK”.

The result was getting all the FKs I wanted added into my model! Viola!

Snowflake with RI

So I can happily report that Philip’s little enhancement works just fine in 4.1.3. WooHoo! I can see this being very useful for a lots of cases in the future.

In a future post (early next year), I will continue with showing how we implemented Referential Integrity constraints in Snowflake DB and if I can generate the DDL from #SQLDevModeler.

Happy New Year Y’all

Kent

The Data Warrior & Snowflake Technical Evangelist

Better Data Modeling: Showing Super & Sub Types in #SQLDevModeler (SDDM)

So this started with a not so innocent tweet from Jeff Smith:

//platform.twitter.com/widgets.js

Well, I sort of answered at least part of the question (eventually),  but along the way the topic of using super types and sub types came up.

Note: If you don’t know what a sub type is, you probably do not do conceptual or logical modeling, so you can stop reading now. Or google it. 🙂

So, in Oracle SQL Developer Data Modeler (SDDM for short, or #SQLDevModeler) you can specify sub type entity relationships in the Logical Model (not relational or physical).

Unless I missed an enhancement (??), you have to do this by:

  1. Create the parent or super type entity
  2. Create the potential sub type entity
  3. Set the Super Type Entity property on the candidate Sub Type Entity to associate it with the parent.
Set Super Type

Set Super Type

Note in the screen that Super Type is set to Employees.

(It sure would be nice if we could just drag and drop to do this, or better just create a new sub type entity “inside” an existing entity)

Once you have set the property, then it will appear in the diagram in one of several ways, depending on the diagram notation you pick. The default is Barker Notation with Box-in-Box Presentation turned on. That looks like this:

Displaying Subtypes in Barker Notation with Box-in-Box

Displaying Sub Types in Barker Notation with Box-in-Box

If you turn Box-in-Box off (right mouse on white space in the diagram then go to Notation), you can drag the sub types outside the super type display and a red line will be displayed to connect them together.

If you switch to Bachman Notation with Box-in-Box off, it looks like this:

Displaying Subtypes in Bachman Notation

Displaying Sub Types in Bachman Notation

Notice the little red lines with arrows pointing into the Employees entity? That is the sub type relationship.

So depending on your personal experience and style, you have a few options to choose from when modeling these type of relationships.

How this converts to a database table design is a whole other (and longer) topic. If you really need to know now, go buy Heli’s SQL Dev Modeler Book and read the section on Inheritance.

Or you could sign up for my online Intro to SDDM (use coupon code GRAZIANO10S for 20% off).

Better Still – do BOTH!

Happy Modeling

Kent

The Data Warrior

P.S. I will be speaking at ECO15 in Raleigh, NC next week. If you are attending be sure to say hi.

Better Data Modeling: The best FREE data modeling tool just got better!

Yes, it true Virginia, the is a Santa Claus!

And this year Santa brought you a new, improved version of the best FREE data modeling tool in the known universe: Oracle SQL Developer Data Modeler 4.0.

The team at Oracle went all out this year and produced three (yes three) pre-release versions to make sure all the fixes and new features were rock solid before they called it production.

That is a lot of testing and work.

But worth the effort – they fixed piles of bugs and added dozens of new features.

Oracle product manager Jeff Smith (@thatjeffsmith) has already published several articles highlighting his favorite new features. Check out what he has to say here then go download the new version and give it try.

Let me know what you your favorite new feature is.

Merry Christmas!

The Oracle Christmas Elf

(Kent)

P.S. Without proven methods and standards, even the best tool will not insure you build the best model, so why not increase your chances by giving yourself the gift of knowledge by picking up a copy of my data model checklist book (on sale for a few more hours).

 

Better Data Modeling: New and Improved Oracle SQL Developer Data Modeler (#SQLDevModeler)

Yup, my friends at Oracle have been hard at working enhancing what was already the best FREE data modeling tool out there.

They just released SDDM R4 EA3! You can go get it right now: http://www.oracle.com/technetwork/developer-tools/datamodeler/downloads/datamodeler-4ea-downloads-1988443.html

As always there are both new features and bug fixes.

One of the coolest new features is the ability to show entity (or table) comments right on the diagram in the object. This will be very useful for enabling data model reviews with the business users.

Product manager Ashley tweeted and example the other day:

 

For even more details and ideas how to use this feature check out Jeff Smith’s post on the feature here.

So what are you waiting for? Go get it today!

Data Modeling is Fun!

Later

Kent
The Oracle Data Warrior

Post Navigation

%d bloggers like this: