Database Geek Blog » Learn Oracle

Designing the Data Mart – Part 2

Lewi — Mon, 18 May 2009 14:21:00 +0000

Continuing from Part 1.

So now we have our transactional model and a basic user story:

Our first request from the business for our data mart is that they want to be able to query all of the orders by date, by customer and/or by region (state, city or country). They want to be able to aggregate (sum and average) across those items.

The first thing we need to do is talk to the… Read the rest!

Designing the Data Mart – Part 1

Lewi — Sat, 16 May 2009 14:35:00 +0000

As I mentioned a while back (a loooong while back), I have been thinking about writing up how I design data marts. The problem with that is that it is a huge topic. Even converting an existing schema (which doesn’t always exist) to a data mart (star schema style), still takes plenty of behind the scenes data analysis and prepwork. Still, I am not going to take a shot at it.

I could start with… Read the rest!

PL/JSON v0.6.2 Released

Lewi — Sat, 09 May 2009 12:58:22 +0000

It was pointed out to me that I had a few errors in the previous release. Those have been fixed and the install should go a lot smoother now. No additional functionality here, just bug fixes. If you tweaked the previous release to install it, you don’t need this one.

As always, you can download the new code directly from the PL/JSON SourceForge page.

Change Log:

Version: 0.6.2
Fixed exit commands in various code… Read the rest!

PL/JSON v0.6 Released to SourceForge

Lewi — Mon, 27 Apr 2009 11:21:20 +0000

From the Database Geek.

PL/JSON v0.6.1 has now been released to Sourceforge.net. The reason for the .1 is that I forgot a dependency on the 0.6 release.

Anyway, PL/JSON can now create JSON via the API or through parsing a text string. The parser is implemented as a stand along package. That means you can write your own parser (or use an external procedure) if you don’t like mine. This will make it very extensible.… Read the rest!

Use a Pipelined Function to Select Source Code Arguments

Lewi — Thu, 23 Apr 2009 22:01:27 +0000

From the Database Geek.

I recently needed to query all of the arguments to the various stored procedures, functions, packaged objects and types. Oracle provides all of this information in the data dictionary in the ALL_PROCEDURES and ALL_ARGUMENTS views. The problem with this is that it’s kind of kludgey to suck out all of the pertinent data.

One problem is that arguments for procedures and functions in packages is access differently than arguments for stand… Read the rest!

Stupid Database Tricks – Shutdown the server from a stored procedure

Lewi — Sun, 19 Apr 2009 19:38:15 +0000

From the Database Geek.

I’m not even going to try to explain why I wrote this. Let’s just say that it comes in handy on occasion.

What this very simple procedure does is use DBMS_SCHEDULER to execute a shutdown command in windows. This could easily be adapted to Unix and/or Linux.

Use at your own risk. By default you get a 30 or 60 second delay (depending on windows version, I think) before the shutdown/reboot.… Read the rest!

ORA_Tweet Now Does Short URLs

Lewi — Sat, 11 Apr 2009 12:57:08 +0000

Paul Gallagher, of the Tardate blog, emailed me this morning (or I guess it was last night) and sent me some code to enhace ORA_Tweet. He wrote a package to call out to an is.gd API to convert a long URL to a short URL. The really cool thing is that he used a regular expression to find matches INSIDE the comment body. That means that ANY URLs will be replaced with a short URL,… Read the rest!

Calculating Business Days and Business Days Between

Lewi — Mon, 06 Apr 2009 19:13:06 +0000

From the Database Geek.

I recently had a requirement to populate the day dimension of a data mart (I won’t put all of the code here as it’s pretty large). That’s not that big deal but part of the requirement was to set several columns: BUSINESS_DAY_FLAG, BUSINESS_DAY_NO and BUSINESS_DAYS_REMAINING_NO.

The BUSINESS_DAY_FLAG is Y is the date is MON-FRI and N is the date is SAT or SUN.
BUSINESS_DAY_NO is the business day of the

… Read the rest!

Private vs Public Global Variables

Lewi — Wed, 01 Apr 2009 15:47:08 +0000

Recently I posted an article about ORA_Tweet, an Oracle Twitter Client. I was asked by someone reading the code why I put several variables in the BODY of the package rather than the SPEC. The question was posed something like this:

Why not put the variables in the package spec where they are modifiable? That would involve less maintenance.

I specifically put them in the body so that they are not modifiable. I don’t… Read the rest!

JSON In (and out) of Oracle – JSON Data Type

Lewi — Wed, 25 Mar 2009 11:04:55 +0000

From the database geek.

Update March 29, 2009: PL/JSON is now available as an open source project (MIT License). Read the FAQ at http://oracleoss.com

Do you use JSON? Do you use Oracle? How would you like to use JSON in Oracle? How would you like to store it, generate it and read it? I am creating a new JSON data type that will work like XMLType.

I am assuming you are familiar with Oracle (or… Read the rest!

Ora_Tweet – Tweet From Oracle, A PL/SQL Twitter API

Lewi — Sun, 15 Mar 2009 16:01:05 +0000

Get the latest source from the ORA Tweet project page at sourceforge.

I had some free time this last Saturday night (after the family was all in bed) and I wanted to do a little mini-project. I don’t get to do enough PL/SQL anymore so I like to look for utilities and smaller fun things to code. While I was thinking about it, I was also following along on twitter to the posts that the… Read the rest!

Oracle Data Types – 5 FAQs About Number

Lewi — Fri, 13 Mar 2009 15:25:42 +0000

I get a lot of email, and comments on blog entries, asking questions about many different topics. I am going to try to answer some of the more common questions as FAQs. Today I am starting with some NUMBER FAQs. I am specifically talking about Oracle and I am specifically talking about the NUMBER data type, not numerics in general. I’ve written about NUMBERs before.

Q: What is the difference between an INTEGER and a

… Read the rest!

Advanced Queues and Streams: A Definition in Plain English

Lewi — Mon, 09 Mar 2009 02:11:27 +0000

A mathematician, an accountant and an economist apply for the same job. The interviewer calls in the mathematician and asks “What do two plus two equal?”

The mathematician replies “Four.”

The interviewer asks “Four, exactly?” The mathematician looks at the interviewer incredulously and says “Yes, four, exactly.”

Then the interviewer calls in the accountant and asks the same question “What do two plus two equal?” The accountant says “On average, four – give or take… Read the rest!

Oracle Advanced Replication: A Definition in Plain English

Lewi — Mon, 09 Mar 2009 02:05:00 +0000

What is Replication?

According to Webster’s Online, the definition we mean is: 3 a : COPY, REPRODUCTION b : the action or process of reproducing

Replication is simply copying data from one database to another. This could be a subset of the data or a complete copy.

I’m going to use insert for my examples but any DML can be replicated.

If you create an insert trigger on a table and push data across a… Read the rest!

uCertify Oracle Certification Software Review

Lewi — Tue, 17 Feb 2009 22:16:30 +0000

From the Database-Geek.

In addition to frequently being asked to recommend books for newbies to Oracle, I am also asked for guidance on certification. Basically, what materials are available and worth purchasing. I used Self Test software and the Sybex books when I was working on my certification. That was back in the 9i days. If you are working on 9i certification, I strongly recommend them.

However, I figure… Read the rest!