Posts

Showing posts from 2014

Three New Members of the Oracle Database Evangelist Team

Image
A long, long time ago....I announced that I had been given the honor of assembling a team of evangelists, whose job would be to promote Oracle Database as an application development platform.

In other words, make sure that current and future users fully leverage all the amazing features for developers that are baked into Oracle Database, such as SQL, PL/SQL, Oracle Text, Oracle Spatial, edition-based redefinition and more.

I am very pleased to announce that my team has now swelled dramatically from one person (me) to four, with one more to come on board in early 2015.

I will make a more "formal" announcement of our team and our plans in Q1 2015, but for now, I did want to share the joyful feeling I feel.

Drum roll, please....


Todd Trichler, Community Manager

Todd got his start at Oracle working with Partners in Alliances. For over a decade he has been focused on technology outreach, working closely with development to drive "grass-roots" engagements in both Oracle an…

Tim Hall: PL/SQL presenter extraordinarie

If it's PL/SQL, I'm interested. And if it's PL/SQL involved in winning some sort of award, well, I am downright excited.

So I was very pleased indeed to see that Tim Hall of Oracle-Base fame won the UK Best Speaker award at UKOUG 2014 for his talk on Improving the Performance of PL/SQL Function Calls from SQL.

Tim is an engaging writer and speaker, but of course that's not while he won the award. It was because the topic he chose was so incredibly important and exciting.

Still, I thought it would at least be polite to say to Tim:

Congratulations, Tim! Keep up the great work!
Tim is one of those Oracle experts (and an ACE Director to boot) who is incredibly generous with his time and knowledge, as anyone who has spent any time on Oracle-Base.com will know. He can also be quite hilarious, as you can tell from his recent blog post on UKOUG 2014.

Here are links to the slide deck, demo scripts and an article all focused on improving the performance of PL/SQL function calls f…

SQL is Dead (NOT), Long Live SQL!

I participated in an Oracle Academy Ask the Experts webcast in November 2014, with the title "The Code Under the Covers, aka the Database Under the App."

The objective of the webcast was to encourage professors to teach, and students to learn, SQL (the Structured Query Language) and PL/SQL (Procedural Language extensions to SQL). In preparing for the talk, I found myself thinking about Platonic Idealism. Strange, eh?

So I thought I'd share some of these thoughts on my blog. I hope you find them interesting enough to share and comment.

First, it is very much worth noting that while SQL is "old" - the first commercial SQL database was released by Oracle waaaay back in 1979 -  it's not going anywhere. In fact, it is getting more important than ever, more entrenched, and more widely used.

And I think that part of the reason for the stickiness of SQL has to do with the aforementioned Platonic Idealism, or to be more precise, it has to do with how different the u…

Feedback on my Planning for Trouble Oracle Magazine article

Received feedback today from James S on my latest Oracle Magazine article, Planning for Trouble. I will respond here (there is no mechanism for comments/discussion at the Oracle Magazine page). If you haven't yet read it, I suggest you do so before proceeding with this post.
Comment 1. This is regarding exception handling.  Let’s say the client calls procedure A, and A calls B, B calls C. Are you suggesting we add a “When others” + error logging logic in each level? Does it mean one error will be logged three times? (because it is captured and re-raised each time).
Good point, James. I make the argument in the article that you should trap the exception as close as possible to where it was raised, so that you can log the values of local variables that may help you diagnose the problem. 

[Here's reinforcement of that point (and other great points about doing effective execution tracing) - they call it contextual logging: http://www.stackify.com/smarter-errors-logs-putting-data-work

Planning for trouble: comments on my latest Oracle Magazine article.

In my November/December 2014 article for Oracle Magazine, Planning for Trouble, I urge developers to realize that regardless of best intentions, not everything related to our apps is under our control, and we need to assume that trouble might be coming our way.

I received today, the following comments from Gary Malandro, which I thought you might enjoy reading:

Enjoyed your article in Oracle Magazine, and I have a few comments.
1.You mentioned “Documents that spell out naming conventions…fit very nicely inside desk drawers”.  On our team, we have a number of policies that include the requirements for a technical design document, a software change request, source control, and some regarding style.  First thought upon hearing that is probably what-a-load-of-bureaucratic-nonsense.  Well, there are reasons for creating and enforcing these standards.  Compliance for one.  Another is we had code going into production systems that performed poorly, contained logic errors, was difficult to und…

FORALLs and COMMITs

Received this note today from Debbie B:

I attended your Turbo Charge PL/SQL seminar today. I still have a question about where to put COMMIT. I’m using 10g. See (pseudo) code below.
Say I have 50,000 records and the LIMIT is 100. If an exception is thrown: Do I need a COMMIT in the WHEN clauses so successful DML gets committed, then loop processing will continue?I was thinking each DML needed it’s own BEGIN EXCEPTION END block so I would know if the error happened due to the insert or the update and could log the appropriate error. Is this wrong?
  OPEN v_cursor;   LOOP     FETCH v_cursor BULK COLLECT INTO data_array LIMIT i_limit;     EXIT WHEN data_array.COUNT = 0;
    BEGIN       FORALL i IN 1.. data_array.COUNT SAVE EXCEPTIONS         INSERT INTO some_table VALUES data_array (i);         COMMIT;     EXCEPTION         WHEN dml_errors THEN              log_error;              COMMIT;              /* Don't RAISE, so execution will continue */         WHEN OTHERS              log_error;             …

Dinodate, PL/SQL as Scripting Language Liberator, watch the show!

Image
As I mentioned in a previous post, I had an awful lot of fun with Christopher Jones doing our PL/SQL: The Scripting Language Liberator talk at OOW. PL/SQL: The Scripting Language Liberator: While scripting languages go in and out of favor, Oracle Database and PL/SQL persist, managing data and implementing business logic. This session walks through a web application to show how PL/SQL can be integrated for better logic encapsulation and performance; how Oracle's supplied packages can be used to enhance application functionality and reduce application complexity; and how to efficiently use scripting language connection and statement handling features to get better performance and scalability. Techniques shown in this session are applicable to mobile, web, or midtier applications written in languages such as JavaScript, Python, PHP, Perl, or Ruby on Rails. Using the right tool for the right job can be liberating. Once word got out around Oracle that we would be unveiling DinoDate at …

Running out of PGA memory with MULTISET ops? Watch out for DISTINCT!

A PL/SQL team inside Oracle made excellent use of nested tables and MULTISET operators in SQL, blending data in tables with procedurally-generated datasets (nested tables). 

All was going well when they hit the dreaded:
ORA-04030: out of process memory when trying to allocate 2032 bytes 
They asked for my help. 

The error occurred on this SELECT:
SELECT  *
   FROM header_tab trx
   WHERE (generated_ntab1 SUBMULTISET OF trx.column_ntab)
      AND ((trx.column_ntab MULTISET
            EXCEPT DISTINCT generated_ntab2) IS EMPTY)
The problem is clearly related to the use of those nested tables. Now, there was clearly sufficient PGA for the nested tables themselves. So the problem was in executing the MULTISET-related functionality.

We talked for a bit about dropping the use of nested tables and instead doing everything in SQL, to avoid the PGA error. That would, however require lots of work, revamping algorithms, ensuring correctness, you know the score.

Then my eyes snagged on the use of DISTINCT an…

The PL/SQL Whisperer

[oreiginally published at FeuerThoughts in December 2011]

I spent two days in Berlin, training 25 developers at an event sponsored by DOAG. Then I headed over to the Netherlands to spend a couple of days with 37 developers at an AMIS-sponsored training.

But on Tuesday, after I completed the first day of training without the assistance of a microphone, my voice said "Bye, bye!" I woke up Wednesday morning to discover I had lost the ability to speak above a whisper. DOAG hustled, did what was necessary, and brought in a portable microphone/speaker system. AMIS made certain to have the same ready to go on Thursday. 

And so for three straight days, I whispered about new features of PL/SQL in 11g and much more besides. The attendees were very good natured about this less than optimal situation. One person said it made the whole class more exciting - it was as though I was giving away secrets, that no one should hear- except for the very special people in attendance.

Several students …

My Ninth OOW - and first as an Oracle employee

Image
Before heading out to San Fran last Thursday for meetings and the ACE Director briefing, I happened to pick up my Oracle PL/SQL Advanced Programming with Packages (my second book, published in 1996, immediately following up from the 1995 publication of my Oracle PL/SQL Programming text at IOUW in Phillie). 
Here’s what I found taped inside the cover:


That was the first Oracle Open World ever, and I was still working for SSC, the consulting firm I joined when I left Oracle in 1992. Must confess: don’t remember anything about OOW96, but I know how to count. Here’s some OOW math:
I have attended OOW96, 97, 98, 99 2000….2014: nine Oracle Open Worlds. During that time I published nine books on PL/SQL and one (with primary author Guy Harrison) on MySQL Stored Procedures; I wrote one or two automated testing frameworks for PL/SQL, and racked up 2M miles on American Airlines - ignoring my family as I traversed a sizeable chunk of human-occupied Earth presenting on PL/SQL.
OOW14 was, however,…

Coming down to earth at OOW14

Before I joined Oracle, I was honored to be an ACE Director for several years, and boy did I get spoiled. Especially at Oracle Open World time.

Oracle paid for my airfare and hotel. They set up the hotel reservation. They picked me up in (non-stretch) limo and delivered me to that hotel. They drove me back to the airport. Nice....

Then I rejoined Oracle in March of this year.

In late August, I was talking with a friend at Oracle and mentioned that I had yet to arrange my hotel.

"Whaaaat?" she practically screeched in the phone. "You don't have your hotel? Oh, Steven, you better get on that right away."

Turns out I had received an email on 7 July saying, in effect, "Congrats, Steven as Oracle employee. We have confirmed your registration for the now. NOW GO RESERVE YOUR HOTEL ROOM."

But I didn't notice that last part. Just filed the email away.

So I followed the advice of my friend, and went on-line to get my hotel reservation set up.

Guess what? I…

Use COLUMN_VALUE when selecting from scalar table function

Received this question today:

I don’t have a problem to select from collection when collection is based on objects with columns/attributes. What about a collection defined as:

TYPE list_of_numbers_t IS TABLE OF NUMBER;

What would be the column name when you select from the collection?

Short answer:

COLUMN_VALUE

Longer answer: here's a script I used to demonstrate several different features of nested tables. See query at bottom.

CREATE OR REPLACE TYPE list_of_names_t
   IS TABLE OF VARCHAR2 (100);
/

GRANT EXECUTE ON list_of_names_t TO PUBLIC
/

DECLARE
   happyfamily     list_of_names_t := list_of_names_t ();
   children        list_of_names_t := list_of_names_t ();
   grandchildren   list_of_names_t := list_of_names_t ();
   parents         list_of_names_t := list_of_names_t ();
BEGIN
   /* Can extend in "bulk" - 6 at once here */
   happyfamily.EXTEND (6);
   happyfamily (1) := 'Veva';
   happyfamily (2) := 'Chris';
   happyfamily (3) := 'Lauren';
   happyfamily (…