What's in a name? The establishment and enforcing of naming conventions is often one of the first duties to be tackled when implementing new software. Adequate thought and preparation is required in order for such a task to be successful. What amount of effort should be extended in the creation of appropriate database naming standards? Are current industry standards acceptable?Shakespeare, many, many years ago, may have said it best when he wrote: "What's in a name? That which we call a rose by any other name would smell as sweet." But, if that...
Tuesday, 28 November 2006
Tuesday, 21 November 2006
Character Versus Numeric Data Types
Posted on 09:30 by Unknown
Most DBAs have faced the situation where one of their applications requires a four-byte code that is used to identify products, accounts, or some other business object, and all of the codes are numeric and will stay that way. But, for reporting purposes, users or developers wish the codes to print out with leading zeroes. So, the users request that the column be defined as CHAR(4) to ensure that leading zeroes are always shown. But what are the drawbacks, if any, to doing this?Well, there are drawbacks! Without proper edit checks, INSERTs and UPDATEs...
Tuesday, 7 November 2006
DB2 Access Paths and Change Management Procedures
Posted on 22:20 by Unknown
No one working as a DB2 DBA or performance analyst would deny that one of the most important components of assuring efficient DB2 performance is making sure that DB2 access paths are appropriate for your DB2 programs. Binding programs with EXPLAIN(YES) specified is important to ensure that we know what access paths DB2 has chosen for each SQL statement. Without the information that EXPLAIN puts in the PLAN_TABLE we would be "flying blind."Anyway, programs need to be rebound periodically to ensure that DB2 has forumlated access paths based on up-to-date...
Monday, 6 November 2006
Try Out the XML Capability of DB2 9 for Free
Posted on 12:54 by Unknown
Are you aware that there is a version of DB2 that you can use free of charge? It is called DB2 Express-C and it is basically IBM's way of removing price as being the issue in terms of you trying out and using DB2. Think of it as a way to use DB2 just like you would use an open source DBMS (except you don't get the source code).According to IBM: DB2 Express-C is a version of DB2 Express Edition (DB2 Express) for the community. DB2 Express-C is a no-charge data server for use in development and deployment of applications including: XML, C/C++, Java,...
Monday, 30 October 2006
New DB2 for iSeries Redbooks
Posted on 09:24 by Unknown
I don't usually cover DB2 on the iSeries (you may still be calling it the DB2/400 or DB2 for the AS/400). But this week saw the release of two new redbooks on DB2 for iSeries, so I thought I'd mention them briefly here.The first new redbook covers stored procedures, triggers, and user-defined functions, and it is called, appropriately enough, Stored Procedures, Triggers, and User-Defined Functions on DB2 Universal Database for iSeries. This redbook covers some of the announced features for stored procedures, triggers, and UDFs in V5R1, V5R2, V5R3,...
Friday, 27 October 2006
IBM Second in Software Sales
Posted on 13:06 by Unknown
The San Francisco Chronicle reported today that IBM is officially the second largest software provider, bypassing former number two Oracle, but still behind number one Microsoft:In its most recent quarter, IBM software generated $4.4 billion in revenue, and it's the company's main profit generator, with an 85 percent profit margin. Thirty-seven percent of IBM's profit comes from software. In 2005, it sold $15.8 billion worth of software, topping the $14.4 billion that Oracle posted in fiscal 2006, which ended June 30. I find this news interesting....
Thursday, 26 October 2006
DB2 9 for z/OS Article
Posted on 13:57 by Unknown
Just a short blog post here to point everyone to an article I wrote for DB2 Magazine offering a high-level overview of what is coming with DB2 9 for z/OS. Note that there is no "V" before the "9" - that is courtesy of IBM marketing...Anyway, the article is titled DB2 9 for z/OS Roars to Life. Check it out for a short introductory article covering the highlights of the next version of DB2 for z/OS, including coverage of XML, online schema evolution advances, new query capabilities, security and performance improvements, and a discussion of what...
Monday, 23 October 2006
Check out New IBM Information Management Blog Site
Posted on 09:48 by Unknown
IBM has launched a new blog site for Information Management. The site offers multiple blogs written by IBM product managers, technical architects, marketing managers and strategists. These folks will blog about issues and trends in information management... as well as IBM products that support information management.Recent posts cover last week's IBM Information on Demand conference, Informix 4-GL, and the impact of unstructured information on business intelligence. I'm sure I'll be checking this site out regularly for tidbits of news on what...
Saturday, 21 October 2006
DB2 9 pureXML Guide
Posted on 22:33 by Unknown
Another new redbook that should be of interest to DB2 for z/OS users is the DB2 9 pureXML Guide. Although this redbook covers the pureXML feature from a DB2 LUW perspective, pureXML will also be a feature of DB2 9 for z/OS when it becomes generally available next year (2007).The redbook discusses the pureXML data store, hybrid database design and administration. It also describes XML schema, industry standards, and how to manage XML schemas. Other features and examples covered include SQL/XML, XPath, and XQuery...XQuery is the only one of these...
DB2 for z/OS: Data Sharing in a Nutshell
Posted on 15:55 by Unknown
Just a short blog entry this week to let everyone know about a new IBM redbook titled "DB2 for z/OS: Data Sharing in a Nutshell."This redbook is an essential read for anyone who is interested in expanding their knowledge of DB2's usage of data sharing. According to the redbook website, "(t)his IBM Redbook is meant to facilitate your journey towards data sharing by providing a cookbook approach to the main tasks in enabling data sharing and workload balancing. It does not have all the answers, because it is a brief summary of a large field of knowledge,...
Tuesday, 10 October 2006
IDUG Europe 2006 Synopsis
Posted on 11:02 by Unknown
For those folks who do not follow my other blogs, I just wanted to make sure that you saw the series of posts I ran summarizing the European IDUG conference last week in Vienna, Austria. Here are the links for the four posts:IDUG in ViennaIDUG Europe - Day OneIDUG Europe - Day TwoIDUG Europe - Day ThreeIf, after reading about the just-completed European IDUG, you want to attend an IDUG event yourself, here are links to IDUG's upcoming conferences:IDUG 2007 Australian Forum - March 29-30, 2007 in MelbourneIDUG 2007 North American Conference - May...
Wednesday, 4 October 2006
IBM Plans Initiative to Keep Mainframes Humming Along
Posted on 04:16 by Unknown
Just read this story on Yahoo news about IBM's effort to simplify programming for mainframe computers. The story talks about IBM's on-going efforts to keep the mainframe relevant and useable. Even though it uses a lot of condescending terms like referring to mainframes as "warhorses" and "dinosaurs," the article is worth a quick read if you are a mainframe proponent.The best news is that IBM plans to spend $100 million over the next five years to simplify mainframe operations and management. Now that is good news, inde...
Sunday, 24 September 2006
Sequence Objects and Identity Columns
Posted on 14:51 by Unknown
When designing DB2 databases a frequently heard request is for a column that contains sequentially generated numbers. For example, each row has a counter associated with it. When a new row is inserted, the counter should be incremented by one for the new row. This way, each new DB2 row has a unique “row number” associated with it. Until recently such a design was difficult to deliver.Without sequence objects or identity columns an application program can implement similar functionality, but usually not in a manner that performs adequately as database...
Friday, 15 September 2006
The Path to an Executable DB2 Program
Posted on 11:41 by Unknown
Here is another Q+A exchange that I thought might be useful to share with everyone here on the blog:QUESTION: Could you please explain the difference between a package and a plan, the process of precompilation, compilation and running a COBOL DB2 program as well as a COBOL CICS DB2 program?ANSWER: Well, I'll hit the highlights in response to your question but if you really want an in-depth answer then you should read the DB2 manuals (or a book like DB2 Developer's Guide).What is a plan? A plan is an executable module containing the access path...
Wednesday, 6 September 2006
Help for SAP Shops Using DB2 for z/OS
Posted on 14:01 by Unknown
Just a quick blog post today to alert folks to a relatively new blog focusing entirely on SAP usage with DB2 for z/OS. According to the blogger, Omer Brandis:Whether you have already implemented SAP on DB2 for z/OS, or are just seriously considering it, this is the blog for you. This blog will deal with real issues from the point of view of a true real-world professional, discussing the good, bad, and ugly of SAP on DB2 for z/OS.Recent posts have covered offsite recovery, reorganizing SAP OFFICE, and hidden REORG jobs. If you use SAP and DB2 on...
Friday, 1 September 2006
The Two Biggest DB2 Performance Things
Posted on 09:00 by Unknown
DB2 performance is one of those perennial topics that people just can't seem to get enough of. I guess that is because the performance of applications is one of the bigger issues that end users complain about. And DBAs can be heroes if they can resolve performance problems quickly. It alos could be that performance problems are so ubiquitous because people keep on making the same design and coding mistakes...With all of that in mind, let's take a look at what I think are the two biggest things you need to get control of to keep DB2 and SQL performance...
Thursday, 31 August 2006
Accessing Partitioned Data
Posted on 08:12 by Unknown
One area that tends to confuse some DB2 developers until they gain experience is how DB2 partitioning works. A common question I get goes something like this: “If a table is in a partitioned table space, say four partitions, for example, then to process the table in batch can I run four instances of the batch program in parallel, one against each partition. What do I code to do this?”Well, the short and sweet answer to this question is “Yes, you can run four instances of a batch program in parallel if you so desire.” But there is a nuance to this...
Tuesday, 29 August 2006
How are Indexes Being Used?
Posted on 12:31 by Unknown
In keeping with my promise to periodically post blog entries based on questions I have received, here we have another question I have been asked:If I have five indexes on a table, what is the best way to determine if all, some or none of the indexes are being used?Here is the answer I sent:The best approach would be to make sure you have run EXPLAIN on all of your production plans and packages. Then examine the PLAN_TABLE output for those indexes. For example:SELECT *FROM my.PLAN_TABLEWHERE ACCESSNAME IN (put your list of indexes here); Of course,...
Thursday, 24 August 2006
VARCHAR versus Compression
Posted on 10:55 by Unknown
A couple of days ago I posted a blurb giving advice on using variable character columns in DB2. After thinking about the topic a little bit more, I decided to post a follow-on topic: namely, comparing the use of VARCHAR to DB2 compression.Even though these are two entirely different "things," they are each probably done for similar reasons - to save disk storage. VARCHAR does this by adjusting the size of the column to fit the actual length of text being stored; compression does this by sending rows of data through an algorithm to minimize its...
Monday, 21 August 2006
IBM Mainframes - Not Just for Big Shops Any More
Posted on 12:42 by Unknown
Just a quick blog today to point you to an interesting article in the latest issue of IBM Systems Magazine - Mainframe Edition. The article, titled A New System for a New Market, points out that the System z9 Business Class (z9 BC) platform, the latest mainframe in IBM's product line announced in April 2006, is suitable for the small and medium business (SMB) space.This offering brings high performance and scalability to the SMB market at a very reasonable cost (around $100k). With specialty engines that can be added (IFL, zIIP and zAAP), again...
Sunday, 20 August 2006
Advice on Using Variable Character Columns in DB2
Posted on 21:36 by Unknown
One of the long-standing, troubling questions in DB2-land is when to use VARCHAR versus CHAR. The high-level advice for when to use VARCHAR instead of CHAR is for larger columns whose length varies considerably from row-to-row. Basically, VARCHAR should be used to save space in the database when your values are truly variable.In other words, if you have a 10-byte column, it is probably not a good idea to make it variable... unless, of course, 90% of the values are only one or two bytes, then it might make some sense. Have you gotten the idea here...
Thursday, 17 August 2006
Greatest Software Ever?
Posted on 14:05 by Unknown
I just stumbled across a very interesting article this afternoon and thought I'd share it with everybody through my blog. The article, published in Information Week is titled What's The Greatest Software Ever Written? And isn't that an intriguing question?Well, I read through the article and other than a few quibbles here and there I'd have to say that the author did a good job of assembling his list. He spends quite a bit of time talking about the IBM 360 project - and well he should. This was one of the first truly huge software projects and...
Thursday, 10 August 2006
SHARE Travelers Take Heed
Posted on 09:17 by Unknown
With the upcoming SHARE conference in Baltimore next week, there are sure to be many of you out there who will be traveling to the nation's capital region over the weekend. As you prepare to travel, be sure to factor in additional time at the airport due to the latest TSA warning.Basically, in response to a recently thwarted terrorist plot in the UK, the threat level has been raised to High (or Orange) for all commercial aviation operating in or destined for the United States. That means the lines will be longer and the searches more thorough...
Wednesday, 9 August 2006
Where exactly is a DB2 plan stored?
Posted on 12:21 by Unknown
The title of this posting is a question I received awhile ago. As I promised earlier on this blog, I will periodically post the answers I have given to e-mailed questions. So, here goes:A DB2 "plan" is stored in the DB2 Directory and information about the plan is stored in the DB2 Catalog.The DB2 Directory table that contains actual plans is SYSIBM.SCT02 (and SYSIBM.SPT01 contains actual packages). The plan is stored as an internal structure called a cursor table; packages are stored as package tables. As DB2 runs application programs, it loads...
Tuesday, 8 August 2006
Mainframe Weekly: A new mainframe-focused blog
Posted on 13:41 by Unknown
Mainframe Weekly is a new blog featuring the insights of Trevor Eddolls. Trevor is an editor who has worked for Xephon for some time. Xephon publishes those "Update" journals - you know the ones, DB2 Update, CICS Update, etc. The ones that are full of content and don't accept any ads.I've had the pleasure of writing for DB2 Update and working with Trevor for a number of years now, and I look forward to regularly reading his new blog. Recent entries there have covered CICS, DB2 and Viper, and storage technology.Do yourself a favor and be sure to...
Monday, 7 August 2006
Upcoming SHARE Conference
Posted on 08:14 by Unknown
Just a quick posting to remind everyone that the bi-annual SHARE conference is coming up next week in Baltimore, MD. For those of you who don't know about SHARE: the conference has offered education to IT professionals, improving the value of IT to businesses, and advancing careers since 1955 - the longest history of any IT user group.SHARE in Baltimore runs from August 13-18, 2006 and, as usual, there will be a plethora of useful and educational sessions on multiple IT topics. According to the folks at SHARE there will be over 800 technical sessions...
Wednesday, 2 August 2006
New Mainframe Redbook
Posted on 13:47 by Unknown
IBM published a new mainframe redbook this week that everyone who works with mainframe technology should download and have handy. It is titled Introduction to the New Mainframe: z/OS Basics and it offers a very nice high-level overview of mainframe technology circa 2006.Of course, if you are a long-time mainframer much of this redbook may be too high level for you. But it will be just the right thing to have at your disposal when someone drops by to ask a basic question. Just e-mail them a copy of the book.And even long-time experts still might...
Monday, 31 July 2006
Network World: Mainframes Still Relevant
Posted on 09:46 by Unknown
Just finished reading a great new article at NetworkWorld.com called Working on mainframes not just for old fogies. Well, that is sure good to know. I may be getting older, but I sure don't think of myself as one of those "old fogies" yet... and I still work on mainframes.The article talks about the continuing relevance of mainframe computing in a novel way -- by talking to several young mainframe newbies. Yes, there are twenty-somethings out there who are working on mainframes, they are just hard to find. And the article makes the point that...
Friday, 28 July 2006
IBM Software Support Toolbar
Posted on 08:54 by Unknown
It seems like everyone under the sun is offering a toolbar to add in to the Internet Explorer browser. Google has one, Yahoo has one, and so do countless others. Now, IBM has one, too.The new IBM Software Support Toolbar plugs into your browser to allow you to search IBM's Support knowledge base using keywords, specific error codes or exact phrases. You can also use it to search or browse for product downloads including Fix Packs, Updates, Patches, etc. So if you have trouble remembering how to get to the IBM site for support, or just want a...
Wednesday, 26 July 2006
How and when to use DB2 scrollable cursors
Posted on 12:44 by Unknown
As I've mentioned here before, sometimes I will use this blog to post answers to questions that have been sent to me. The question being answered today, is this: I have a select query that returns 1000 rows and I want to display the rows from 200 to 500. Could you please let me how to code after the where clause? I know how to get the first 100 rows using -- FETCH FIRST 100 rows only clause. If you are using DB2 V7 or higher, consider using scrollable cursors. With scrollable cursors, you can move directly to the rows you want without having to...
Tuesday, 25 July 2006
Free DB2 Statistics Health Check Software
Posted on 09:32 by Unknown
NEON Enterprise Software SEGUS, Inc. is offering free software for checking the health of the statistics in your DB2 Catalog.Statistics HealthCheck for DB2 z/OS enables you to quickly and effectively analyze and judge the quality of your DB2 Catalog statistics. Checking the health of your DB2 subsystem is especially important considering the heightened sensitivity of DB2 V8 and V9 to bad statistics.The extensive rule system used by Statistics HealthCheck is based on IBM’s own recommendations for maintaining good statistics. Using a violation system,...
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