09 June 2018

Data Migrations (DM): Guiding Principles

Data Migration
Data Migrations Series

Introduction

“An army of principles can penetrate where an army of soldiers cannot."
Thomas Paine

In life as well in IT principles serve as patterns of advice in form of general or fundamental ideas, truths or values stated in a context-independent manner. They can be used as guidelines in understanding and modeling the reality, the world we live in. With the invasion of technologies in our lives principles serve as a solid ground on which we can build castles – solutions for our problems. Each technology comes with its own set of principles that defines in general terms its usage. That's why most of the IT books attempt to catch these sets of principles. Unfortunately, few of the technical writers manage to define some meaningful principles and showcase their usages.

Many of the ideas considered as principles in papers on Data Migration (DM) are at best just practices, and some can be considered as best/good practices. Just because something worked good in a previous migration doesn’t mean automatically that the idea behind the respective decision turns automatically in a principle. Some of the advices advanced are just lessons learned in disguise. Principles through their generality apply to a broad range of cases, while practices are more activity specific.

A DM through its nature finds its characteristics at the intersection of several area - database-based architecture design, ETL workflows, data management, project management (PM) and services. From these areas one can pull a set of principles that can be used in building DM architectures.

Architecture Principles

“Architecture starts when you carefully put two bricks together.”
Ludwig Mies van der Rohe

There are several general principles that apply to the architecture of applications, independently of the technologies used or the industry, e.g. research first, keep it simple/small, start with the end in mind, model first, design to handle failure, secure by design (aka safety first), prototype, progress iteratively, focus on value, reuse (aka don't reinvent the wheel), test early, early feedback, refactor, govern, validate, document, right tool – right people, make it to last, make it sustainable, partition around limits, scale out, defensive coding, minimal intervention, use common sense, process orientation, follow the data, abstract, anticipate obsolescence, benchmark, single-responsibility, single dispatch, separation of concerns, right perspective.

To them add a range of application design characteristics that can be considered as principles as well: extensibility, modularity, adaptability, reusability, repeatability, modularity, performance, revocability, auditability, subject-orientation, traceability, robustness, locality, heterogeneity, consistency, atomicity, increased cohesion, reduced coupling, monitoring, usability, etc. There are several principles that can be transported from problem solving into design - divide and conquer, prioritize, system’s approach, take inventory, and so on.

A DM’s architecture has more to do with a data warehouse as it relies heavily on ETL tasks and data need to be stored for various purposes. Besides the principles of good database design, a few other principles apply: model (the domain) first, denormalize, design for performance, maintainability and security, validate continuously. From ETL area following principles can be considered: single point of processing, each step must have a purpose, minimize touch points, rest data for checkpoints, leverage existing knowledge, automate the steps, batch processing.

 In addition, considering their data-specific character, a DM can be regarded as one or several data products, though in contrast with typical data products DM have typically a limited purpose. From this area following principles could be considered: build trust with transparency, blend in, visualize the complex.

Data Management Principles

Considering that a DM’s focus is an organization's data, some principles need to focus on the management and governance of Data. Data Governance together with Data Quality, Data Architecture, Metadata Management, Master Data Management are functions of Data Management. The focus is on data, metadata and their lifecycle, on processes, ownership and roles and their responsibilities. With this in mind there can be defined several principles supposed to facilitate the functions of Data Management: manage data as asset, manage data lifecycle, the business owns the data, integration across the organization, make data/metadata accessible, transparent and auditable processes, one source of truth.

As part of DM there are customer, employee and vendor information which fall under the General Data Protection Regulation (GDPR) EU 2016/679 regulation which defines the legal framework for data protection and privacy for all individuals within the European Union (EU) and the European Economic Area (EEA) as well the export of personal data outside the EU and EEA. The regulation defines a set of principles that make its backbone: fairness, lawfulness and transparency, purpose limitation, data minimization, accuracy, storage limitation, integrity and confidentiality, accountability [6].

Overseas, the US Federal Trade Commission (FTC) issued in 2012, a report recommending organizations design and implement their own privacy programs based on a set of best practices. The report reaffirms the FTC’s focus on Fair Information Processing Principles, which include notice/awareness, choice/consent, access/participation, integrity/security, enforcement/redress [6].


Project Management (PM) Principles

"Management is doing things right […]"
Peter Drucker

A DM though its characteristics is a project and, to increase the chances of success, it needs to be managed as a project. Managing DM as a project is one of the most important principles to consider. The usage of a PM framework will further increase the chances of success, as long the framework is adequate for the purpose and the organization team is able to use the framework. PMI, Prince2, Agile/Scrum/Kanban are probably the most used PM methodologies and they come with their own sets of principles.

In general, all or some of the PM principles apply independently on whether is used alone or in combination with other PM methodologies: a single project manager, an informed and supportive management, a dedicated team of qualified people to do the work of the project, clearly defined goals addressing stakeholders’ priorities, an integrated plan and schedule, as well a budget of costs and/or resources required [1].

On the other side, an agile approach could prove to be a better match for a DM given that requirements change a lot, frequent and continuous deliveries are needed, collaboration is necessary, agile processes as well self-organizing teams can facilitate the migration. These are just a few of the catchwords that make the backbone of the Agile Manifesto (see [3]).

An agile form of Prince2 could be something to consider as well, especially when Prince2 is used as methodology for other projects. For Prince2 are the following principles to consider: continued business justification, learn from experience, defined roles and responsibilities, manage by stages, management by exception, focus on products, tailor to suit the project environment [2].

All these PM principles reveal important aspects to ponder upon, and maybe with a few exceptions, all can be incorporated in the way the DM project is managed.


Service Principles

Considering the dependencies existing between the DM and Data Quality as well to the broader project, a DM can have the characteristics of a service. It’s not an IT Service per se, as IT only supports technically and eventually from a PM perspective the project. Even if a DM is not a ITSM service, some of the ITIL principles can still apply: focus on value, design for experience, start where you are, work holistically, progress iteratively, observe directly, be transparent, collaborate and keep it simple [4].


Conclusion

“Obey the principles without being bound by them.”
Bruce Lee

Within a DM all the above principles can be considered, though the network of implication they create can easily shift the focus from the solution to the philosophical aspects, and that’s a marshy road to follow. Even if all principles are noble, not all can be considered. It would be utopic to consider each possible principle. The trick is to identify the most “important” principles (principles that make sense) and prioritize them according to existing requirements. In theory, this is a one-time process that involves establishing a “framework” of best/good practices for the DM, in next migrations needing only to consider the new facts and aspects.

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References:
[1] “Principles of project management”, by J. A. Bing, PM Network, 1994 (link)
[2] Axelos (2018) What is PRINCE2? (link)
[3] Agile Manifesto (2001) Principles behind the Agile Manifesto (link)
[4] Axelos (2018) ITIL® Practitioner 9 Guiding Principles (link)
[5] The Data Governance Institute (2018) Goals and Principles for Data Governance (link) 
[6] Navigating the Labyrinth: An Executive Guide to Data Management, by Laura Sebastian-Coleman for DAMA International, Technics Publications, 2018 (link)  

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Koeln, NRW, Germany
IT Professional with more than 24 years experience in IT in the area of full life-cycle of Web/Desktop/Database Applications Development, Software Engineering, Consultancy, Data Management, Data Quality, Data Migrations, Reporting, ERP implementations & support, Team/Project/IT Management, etc.