Welcome!

Microsoft Cloud Authors: Pat Romanski, Elizabeth White, Liz McMillan, Mihai Corbuleac, David Bermingham

Related Topics: PowerBuilder, Microsoft Cloud

PowerBuilder: Article

Distributing Database Modification Scripts to DBAs

The need for ongoing enhancements

I recently read Berndt Hamboeck's article, NetStart' Your PowerBuilder Application after being kindly pointed to it by Bruce Armstrong. It made perfect sense to me to be able to distribute .pbd patches to client machines by having the client-application automatically install them from the application's database. In the lead-up in Berndt's article, he touched on a similar problem - the difficulties of distributing database modification scripts to DBAs prior to the installation of a new executable. In this respect, I had coded functionality for the application I develop to process database modifications from within the application without the need for the DBA's intervention. I tentatively mentioned this to Bruce. (I say ‘tentatively' because I'm a relatively inexperienced programmer). He asked me to write this article.

By way of background, I'm a self-taught PowerBuilder programmer, having been introduced to programming in an ancillary subject at university back in the days of mark-sense cards, Fortran, and Cobol. I am a law enforcement investigator by trade, and designed an application about 15 years ago to process telephone call charge records and financial statements for an Australian law enforcement agency at which I worked. I later engaged a skilled PowerBuilder programmer, Sue Stagg, to set up a commercial version as the New South Wales Police, the fifth-largest police force in the world, wanted to use the application. Unfortunately, Sue had to move on because she started a family, so I took over the programming. I mention this background for two reasons.

The first is as a caveat. Experienced programmers may be able further enhance or refine my methods, which I'll set out below.

The second is that the application I develop (CallRunner) has to be continually enhanced, which invariably includes database changes. The need for ongoing enhancement is because of rapid changes with the technology of mobile phone communications - such as the introduction of Internet access, email, SMS, video, photography, and GPS.

Cellphones have become a valuable source of intelligence for law enforcement. As a demonstration for a new extension to my application, the NSW Police extracted a file of 4400 pages of data from my cellphone. It included historical SMS messages, emails, photographs, and a myriad of GPS locations I'd plotted from all over the county while riding my Harley, as well as the GPS coordinates of where I took my photographs. This data has to be read in and linked to existing data within the application.

In distributing new executables or patches, I'd regularly experience the issues mentioned by Berndt, and I'd often have to spend time at locations where there was no luxury of a DBA.

To save my clients and myself this grief, I created a library entry - call it, say, database.pbl. It included an nvo called nvo_database. A function, of_initialise(), returned the build date and version number as instance variables from the Application Manager.

The fact that modifications were effected from a .pbd meant that if I needed to send out a .pbd patch that relied on database modifications, I could include a database.pbd as well.

Code in the pfc_open event of the Application Manager instantiates unvo_database and calls of_initialise(). Calls are then made from the pfc_open event to at least two like functions in the nvo to effect the database changes.

The first function called from pfc_open manages database changes for the preceding build of the application - just in case the user hasn't installed that version and has jumped to the current release. The second function call is relevant to database changes for the current build. There is an overlap - a ‘boots and braces' approach. You can see from the code below that, as the builds progress, obsolete function calls are remmed. The two valid functions do the work to effect the more recent database changes.

The database modifications typically include:

  • Creating a table
  • Adding a column to an existing table
  • Altering a column in an existing table
  • Adding data to an existing table, or
  • Adding an index

The functionality varies slightly for each but an underlying theme is to trap error codes in the first instance to confirm that a table or column does not exist. If they exist, as they would after the first run of the application, then the change routine is skipped.

The first job of this functionality was to create a table to hold a record of the SQL code used to modify the database. This table held the SQL code, the build date, and the version number of the application, and the date and time the changes were effected. The following is the code initiated from of_database_changes() function of unvo_database ...

The code in the Create Table function is:

The first process in this function is to determine whether the table exists; this is a key function. If the table doesn't exist and returns FALSE, a message is given asking the user whether they want to exit to backup the database.

If the table does not exist, dynamic SQL is used to create the table.

If an error is encountered at any point "Failed on:" is prefixed to SQL code which is saved, whether the changes were successful or not, by way of a call to the function of_save_database_changes(..) in the table just created.

If there is an error at any point, an instance variable, ib_fail, is set to TRUE and, after all subsequent modifications have been processed, a message is given to the user. The DBA can print a report from the database_changes table that will indicate exactly where the error occurred.

The following is the code in the key function of_check_for_existing_table():

A bogus SELECT COUNT call is made on the table. If the table doesn't exist, an error code will be returned. The error code for a non-existing table is 208 and this is compared to an instance constant of that value. The error is trapped and a Boolean value of FALSE is returned to indicate that the table does not exist. If the table exists, TRUE is returned - nothing else needs to be done.

The following is similar code used when adding a column to a table - in this case, column cue_word_sample_text:

Checking and implementing changes for adding indexes or entering data into a table are effected in much the same way. This involves either checking for an error code for the existence of a column or an index, or using SELECT to determine whether data already exists in a table. When using SELECT I found that I had to use SQL Code such that I did not get an error for returning more than one row.

An exception where SQL code could not be used involved the altering of a column width from, say, varchar(100) to, say, varchar(200). With my limited experience I could find no way to use SQL code to determine the attributes of a database column (‘describe' and ‘ColType' clearly only work on the DataWindow object, which is independent to, and may not always comply with, the column description in the table). In such cases, I simply checked the database_changes table to ensure that the SQL has not already been executed.

To guarantee that I was distributing the correct changes and that they will all work as expected, I test the SQL code in the database painter of an auxiliary application. I then copy/paste the tested SQL code into my PowerBuilder development application functions as described. Because my ongoing coding and testing will be contingent on the changes working correctly, I'll quickly establish if there is an error.

I have only had one hiccup and that was where a user had added an index to a column the application was attempting to alter. The DBA was able to print the Database Changes Report and we quickly established where the error occurred from the ‘Failed on' prefix. He dropped the index, re-booted the application to automate the change, and then reinstated the index. All was well.

Following from this, if you wish to alter a column that has an index, you need to code the dropping and reinstating of the index either side of the column alteration.

In this regard, there may be the prospect beyond my knowledge of using SQL to check first and get a handle on an unknown index before altering a column.

Summary
This process has been a tremendous time-saver for me. But more than anything, I can distribute my application with a great deal more confidence. Users are not frustrated or lose confidence in the application because of installation errors. Nor has there been any noticeable deterioration in the start-up time of the application on the first run when the changes are effected.

The sample code can be downloaded here.

More Stories By Bill Beale

Bill Beale is a Consultant/Investigation team leader in a special investigations unit. He studied computing as a sub-major in an Administration degree at the University of Canberra in the 1970s and is a self-taught PowerBuilder programmer, having taken over the ongoing coding and development of applications about five years ago

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
IoT offers a value of almost $4 trillion to the manufacturing industry through platforms that can improve margins, optimize operations & drive high performance work teams. By using IoT technologies as a foundation, manufacturing customers are integrating worker safety with manufacturing systems, driving deep collaboration and utilizing analytics to exponentially increased per-unit margins. However, as Benoit Lheureux, the VP for Research at Gartner points out, “IoT project implementers often ...
"We work in the area of Big Data analytics and Big Data analytics is a very crowded space - you have Hadoop, ETL, warehousing, visualization and there's a lot of effort trying to get these tools to talk to each other," explained Mukund Deshpande, head of the Analytics practice at Accelerite, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Machine Learning helps make complex systems more efficient. By applying advanced Machine Learning techniques such as Cognitive Fingerprinting, wind project operators can utilize these tools to learn from collected data, detect regular patterns, and optimize their own operations. In his session at 18th Cloud Expo, Stuart Gillen, Director of Business Development at SparkCognition, discussed how research has demonstrated the value of Machine Learning in delivering next generation analytics to imp...
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, provided an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profession...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
When people aren’t talking about VMs and containers, they’re talking about serverless architecture. Serverless is about no maintenance. It means you are not worried about low-level infrastructural and operational details. An event-driven serverless platform is a great use case for IoT. In his session at @ThingsExpo, Animesh Singh, an STSM and Lead for IBM Cloud Platform and Infrastructure, will detail how to build a distributed serverless, polyglot, microservices framework using open source tec...
Connected devices and the industrial internet are growing exponentially every year with Cisco expecting 50 billion devices to be in operation by 2020. In this period of growth, location-based insights are becoming invaluable to many businesses as they adopt new connected technologies. Knowing when and where these devices connect from is critical for a number of scenarios in supply chain management, disaster management, emergency response, M2M, location marketing and more. In his session at @Th...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
Cloud Expo, Inc. has announced today that Andi Mann returns to 'DevOps at Cloud Expo 2016' as Conference Chair The @DevOpsSummit at Cloud Expo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited t...
"delaPlex is a software development company. We do team-based outsourcing development," explained Mark Rivers, COO and Co-founder of delaPlex Software, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
IoT is rapidly changing the way enterprises are using data to improve business decision-making. In order to derive business value, organizations must unlock insights from the data gathered and then act on these. In their session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, and Peter Shashkin, Head of Development Department at EastBanc Technologies, discussed how one organization leveraged IoT, cloud technology and data analysis to improve customer experiences and effi...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
The idea of comparing data in motion (at the sensor level) to data at rest (in a Big Data server warehouse) with predictive analytics in the cloud is very appealing to the industrial IoT sector. The problem Big Data vendors have, however, is access to that data in motion at the sensor location. In his session at @ThingsExpo, Scott Allen, CMO of FreeWave, discussed how as IoT is increasingly adopted by industrial markets, there is going to be an increased demand for sensor data from the outermos...
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
The cloud market growth today is largely in public clouds. While there is a lot of spend in IT departments in virtualization, these aren’t yet translating into a true “cloud” experience within the enterprise. What is stopping the growth of the “private cloud” market? In his general session at 18th Cloud Expo, Nara Rajagopalan, CEO of Accelerite, explored the challenges in deploying, managing, and getting adoption for a private cloud within an enterprise. What are the key differences between wh...
Presidio has received the 2015 EMC Partner Services Quality Award from EMC Corporation for achieving outstanding service excellence and customer satisfaction as measured by the EMC Partner Services Quality (PSQ) program. Presidio was also honored as the 2015 EMC Americas Marketing Excellence Partner of the Year and 2015 Mid-Market East Partner of the Year. The EMC PSQ program is a project-specific survey program designed for partners with Service Partner designations to solicit customer feedbac...
The IoT is changing the way enterprises conduct business. In his session at @ThingsExpo, Eric Hoffman, Vice President at EastBanc Technologies, discussed how businesses can gain an edge over competitors by empowering consumers to take control through IoT. He cited examples such as a Washington, D.C.-based sports club that leveraged IoT and the cloud to develop a comprehensive booking system. He also highlighted how IoT can revitalize and restore outdated business models, making them profitable ...
There are several IoTs: the Industrial Internet, Consumer Wearables, Wearables and Healthcare, Supply Chains, and the movement toward Smart Grids, Cities, Regions, and Nations. There are competing communications standards every step of the way, a bewildering array of sensors and devices, and an entire world of competing data analytics platforms. To some this appears to be chaos. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Bradley Holt, Developer Advocate a...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...