Articles

Data Lineage 101: Understanding Its Meaning and Importance

January 30, 2025
Caitlyn Truong

Data lineage is the comprehensive tracking of data usage within an organization. This includes how data originates, how it is transformed, how it is calculated, its movement between different systems, and ultimately how it is utilized in applications, reporting, analysis, and decision-making.

With the increasing complexities of business technology, data lineage analysis has become essential for most organizations. This article provides an overview of the fundamentals, importance, uses, and challenges of data lineage.

The Fundamentals of Data Lineage

Data lineage facilitates improved data transparency, quality, and consistency by enabling organizations to track and understand the complete lifecycle of their data assets. It helps with decision-making when sourcing and using data. It also helps with transforming data, especially for larger organizations with mission-critical applications and intricate data landscapes.

There are several factors to consider with data lineage:

  • Origin: Where did the data originate? The origin might be an application, a database, or a spreadsheet. It could come from another part of the organization or a third-party source.  
  • Flow: How has the data moved across different databases, files, APIs, and internal and external business systems over time?
  • Transformation: Data typically undergoes multiple changes over time due to changes in representation, cleansing, merging with other data, or when the data is generated by or used in a calculation. The changes can also come from data conversions, including ELT (extract, load, transform), ETL, and Reverse ETL processes.
  • Destination: Where is the data now? Does it reside in an application database or data warehouse. Is it used in a report or an analysis? Has it been sent outside the organization?  It may be stored in multiple places.  

The Importance of Data Lineage

Data lineage plays a key role in keeping data valuable and effective in a business setting. Here are a few ways that data lineage can deliver benefits to an organization.

Transparency and Trust

Data has incredible value in an information age. To realize the full value, data must be accurate and accessible. In other words, it becomes trustworthy only when it can be understood by anyone using it, and when the processing steps keep the data accurate. Data lineage provides transparency into the flow of data. It increases understanding and makes it easier for non-technical users to capture insights from existing datasets, especially for aggregated or calculated data.

Compliance and Regulatory Requirements

Data management regulations are becoming more stringent each year. Regulatory standards are tightening, and effective data management is becoming increasingly important. Data lineage can help organizations comply with GDPR, CCPA, and other data privacy laws. The transparency of data lineage makes data access, audits, and overall accountability easier. Accurate data lineage is crucial for demonstrating compliance with regulatory requirements, thereby mitigating the risk of project delays, fines, and other penalties.

Data Governance

Data lineage enables stronger data governance by providing the data to monitor, manage and ensure compliance to issued standards and guidelines. Because data lineage offers traceability of origin, flow, transformation and destination, it allows businesses to improve data quality, reduce inconsistencies and errors, and strengthen data management practices.

Improved Data Quality

Data lineage allows companies to trace the path of data from its current form back to its source. Data lineage offers a transparent record, facilitating the understanding and management of data variability and quality throughout its journey, and ensuring reliable data for decision-making. This is particularly relevant for companies modernizing existing systems.

Facilitating Collaboration Across Teams

With data lineage, trust in data accuracy and accessibility, improved data quality, and stronger ability to govern data all triangulate for better collaboration across teams. Data lineage avoids data siloing and facilitates interdepartmental activity. When data engineers and analysts utilize the same set of data, it fosters cross-functional teamwork and minimizes errors due to bad or in consistent data. Data lineage encourages a sense of unification as team members across an organization work from the same, trusted data.

Real-world Applications of Data Lineage

There are multiple ways that data lineage can add business value to organizations.

Use Case 1: Data Migrations

Zengines has invested in data lineage capabilities to support end-to-end migration of data from existing source systems to new target business systems. Data lineage is often the first research step required to ensure an efficient and accurate data migration.

Use Case 2: Improving Data Analytics

Data lineage exposes data quality issues by providing a clear view of the data journey, highlighting areas where inconsistencies or errors may have occurred. This makes it easier to engage in effective, detailed data analytics.

Consider, for instance, a financial services company with decades-old COBOL programs. Data lineage provides insights for organizations trying to replicate reporting or other outputs from these aging programs.

Use Case 3: Troubleshooting and Root Cause Analysis

Data lineage makes it easier to identify and trace errors back to their source. Finding the root cause of an error quickly is extremely valuable in a world where time is at a premium.

Use Case 4: Enhancing Data Security and Privacy

An important aspect of data security and privacy compliance is keeping data safe guarded at all times. Data lineage provides an understanding of the data life cycle that can show information security groups the steps that must be reviewed and secured.

Comprehensive data lineage makes it easier to demonstrate compliance with data privacy regulations.  For example, Banks and Payments Processors are subject to GLBA (Gramm-Leach-Bliley Act), PCI DSS(Payment Card Initiative - Data Security Standards), EU GDPR (European General Data Protection Regulation), and many other regulations that protect Personally Identifiable Information (PII). The knowledge of how any data element is used allows it to be protected, masked, or hidden when appropriate.

Use Case 5: Implementing Data Mesh and Data Fabric

Data Mesh and Data Fabric are advanced data architectures that help to decentralize data and integrate it across diverse data sources. Understanding the data lineage allows data management teams to make trustworthy data available to Data Mesh / Data Fabric consumers. Data lineage makes it possible to determine the correct data to store and use for a given purpose (decision making, analytics, reporting, etc.). Data lineage is typically part of any new Data Mesh / Data Fabric initiative.  

Challenges in Data Lineage

Data lineage is useful but can also face challenges. Here are a few potential issues.

Data Complexity and Fragmentation

Siloed data continues to be a major hurdle for tracing business data across departments and organizations. Consider when a security trade is being made. The security details are usually maintained in a reference data / Master Data Management application. The bid / ask information comes from many different market vendors and is updated continuously. The trading application computes the value of the trade, and any tax impact is computed in an investment accounting application. Is the same data being used across them all? Do they use different terminology?  Do the applications all use the same pricing information? For accurate reporting and good decision making, it is vital that the same data is used in every step.  

Mapping data lineage in increasingly complex environments is also a concern. Things like on-site and cloud storage, as well as remote, hybrid, and in-person work environments, make data complexity and fragmentation a growing issue that requires attention.

Resource Intensive

Historically, capturing and maintaining data lineage has been resource-intensive work performed by analysts with a deep understanding of the business. Given the quantity of data and code involved, a manual approach is prohibitively expensive for most companies. Most software solutions provide a partial view, only showing data stored in relational databases or excluding logic found in computer programs.

The best option is to find a balance between manual and automated solutions that enable cost-effective data lineage frameworks.

Evolving Data Systems

Data lineage is more than a backward-looking activity. Organizations also need to maintain up-to-date lineage information as systems are changed and replaced over time. In an era of constant change, data lineage teams are challenged to incorporate new forms of data usage or data transformation.

Investing in Data Lineage

Data lineage is becoming a critical part of any company’s data management strategy. In an information age where data and analytics are king, data lineage enables companies to maintain clean, transparent, traceable datasets. This empowers data-driven decision-making and encourages cross-collaborative efforts.

Data lineage addresses a central part of business operations. It provides a powerful sense of digital clarity as organizations navigate increasingly complex tools, systems, and regulatory landscapes.

Forward-thinking technical and non-technical leaders alike should be encouraging their organizations to improve their data lineage strategies. Investments in data lineage result in a valuable new data assets that provide greater business agility and competitive advantage.

Unlock the Power of Seamless Data Lineage with Zengines

Data lineage isn’t just a nice-to-have—it’s essential for modern businesses navigating system changes, compliance pressures, and complex tech stacks. Whether you're migrating from legacy systems, improving analytics, or strengthening data governance, data lineage empowers teams to move faster, reduce risk, and make better decisions.

At Zengines, we’ve built our data lineage capabilities to do more than just document data flow. Our lineage engine integrates deeply with legacy codebases, like mainframe COBOL modules, and modern environments alike—giving you full visibility into how data is transformed, used, and governed across your systems. With AI-powered analysis, automation, and an intuitive interface, Zengines transforms lineage from a bottleneck into a business advantage.

Ready to see what intelligent data lineage can do for your organization?

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RPG and Its Evolution: From Report Generator to Business Logic Powerhouse

IBM's RPG (Report Program Generator) began in 1959 with a simple mission: generate business reports quickly and efficiently. What started as RPG I evolved through multiple generations - RPG II, RPG III, RPG LE, and RPG IV - each adding capabilities that transformed it from a simple report tool into a full-featured business programming language. Today, RPG powers critical business applications across countless AS/400, iSeries, and IBM i systems. Yet for modern developers, understanding RPG's unique approach and legacy codebase presents distinct challenges that make comprehensive data lineage essential.

The Strengths That Made RPG Indispensable

Built-in Program Cycle: RPG's fixed-logic cycle automatically handled file operations, making database processing incredibly efficient. The cycle read records, processed them, and wrote output with minimal programmer intervention - a major strength that processed data sequentially, making it ideal for report generation and business data handling.

Native Database Integration: RPG was designed specifically for IBM's database systems, providing direct interaction with database files and making it ideal for transactional systems where fast and reliable data processing is essential. It offered native access to DB2/400 and its predecessors, with automatic record locking, journaling, and data integrity features.

Rapid Business Application Development: For its intended purpose - business reports and data processing - RPG was remarkably fast to code. The fixed-format specifications (H, F, D, C specs) provided a structured framework that enforced consistency and simplified application creation.

Exceptional Performance and Scalability: RPG applications typically ran with exceptional efficiency on IBM hardware, processing massive datasets with minimal resource consumption. RPG programming language has the ability to handle large volumes of data efficiently.

Evolutionary Compatibility: The language's evolution path meant that RPG II code could often run unchanged on modern IBM i systems - a testament to IBM's commitment to backward compatibility that spans over 50 years.

The Variations That Created Complexity

RPG II (Late 1960s): The classic fixed-format version with its distinctive column-specific coding rules and built-in program logic cycle, used on System/3, System/32, System/34, and System/36.

RPG III (1978): Added subroutines, improved file handling, and more flexible data structures while maintaining the core cycle approach. Introduced with System/38, later rebranded as "RPG/400" on AS/400.

RPG LE - Limited Edition (1995): A simplified version of RPG IV designed for smaller systems, notably including a free compiler to improve accessibility.

RPG IV/ILE RPG (1994): The major evolution that introduced modular programming with procedures, prototypes, and the ability to create service programs within the Integrated Language Environment - finally bringing modern programming concepts to RPG.

Free-Format RPG (2013): Added within RPG IV, this broke away from the rigid column requirements while maintaining backward compatibility, allowing developers to write code similar to modern languages.

The Weaknesses That Challenge Today's Developers

Steep Learning Curve: RPG's fixed-logic cycle and column-specific formatting are unlike any modern programming language. New developers must understand both the language syntax and the underlying program cycle concept, which can be particularly challenging.

Limited Object-Oriented Capabilities: Even modern RPG versions lack full object-oriented programming capabilities, making it difficult to apply contemporary design patterns and architectural approaches.

Cryptic Operation Codes: Traditional RPG used operation codes like "CHAIN," "SETLL," and "READE" with rigid column requirements that aren't intuitive to developers trained in modern, free-format languages.

Complex Maintenance Due to Evolution: The evolution from RPG II (late 1960s) through RPG III (1978) to RPG IV/ILE RPG (1994) and finally free-format coding (2013) created hybrid codebases mixing multiple RPG styles across nearly 50 years of development, making maintenance and understanding complex for teams working across different generations of the language.

Proprietary IBM-Only Ecosystem: Unlike standardized languages, RPG has always been IBM's proprietary language, creating vendor lock-in and concentrating expertise among IBM specialists rather than fostering broader community development.

The Legacy Code Challenge: Why RPG Is Particularly Difficult Today

RPG presents unique challenges that go beyond typical legacy system issues, rooted in decades of development practices:

Multiple Format Styles in Single Systems: A single system might contain RPG II fixed-format code (1960s-70s), RPG III subroutines (1978+), RPG LE simplified code (1995+), and RPG IV/ILE procedures with free-format sections (1994+) - all working together but following different conventions and programming paradigms developed across 50+ years, making unified understanding extremely challenging.

Embedded Business Logic: RPG's tight integration with IBM databases means business rules are often embedded directly in database access operations and the program cycle itself, making them hard to identify, extract, and document independently.

Minimal Documentation Culture: The RPG community traditionally relied on the language's self-documenting nature and the assumption that the program cycle made logic obvious, but this assumption breaks down when dealing with complex business logic or when original developers are no longer available.

Proprietary Ecosystem Isolation: RPG development was largely isolated within IBM midrange systems, creating knowledge silos. Unlike languages with broader communities and extensive online resources, RPG expertise became concentrated among IBM specialists, limiting knowledge transfer.

External File Dependencies: RPG applications often depend on externally described files (DDS) where data structure definitions live outside the program code, making data relationships and dependencies difficult to trace without specialized tools.

Making Sense of RPG Complexity: The Data Lineage Solution

Given these unique challenges - multiple format styles, embedded business logic, and lost institutional knowledge - how do modern teams gain control over their RPG systems without risking business disruption? The answer lies in understanding what your systems actually do before attempting to change them.

Modern data lineage tools provide exactly this understanding by:

Analyzing all RPG variants within a single system, providing unified visibility across decades of development spanning RPG II through modern free-format code.

Mapping database relationships from database fields through program logic to output destinations, since RPG applications are inherently database-centric.

Discovering business rules by analyzing how data transforms as it moves through RPG programs, helping teams reverse-engineer undocumented logic.

Assessing impact before making changes, identifying all downstream dependencies - crucial given RPG's tight integration with business processes.

Planning modernization by understanding data flows, helping teams make informed decisions about which RPG components to modernize, replace, or retain.

The Bottom Line

RPG systems represent decades of business logic investment that often process a company's most critical transactions. While the language may seem archaic to modern eyes, the business logic it contains is frequently irreplaceable. Success in managing RPG systems requires treating them not as outdated code, but as repositories of critical business knowledge that need proper mapping and understanding.

Data lineage tools bridge the gap between RPG's unique characteristics and modern development practices, providing the visibility needed to safely maintain, enhance, plan modernization initiatives, extract business rules, and ensure data integrity during system changes. They make these valuable systems maintainable and evolutionary rather than simply survivable.

Interested in preserving and understanding your RPG-based systems?  Call Zengines for a demo today.

Understanding COBOL: The Backbone of Business Computing That Still Powers Our World

When Grace Hopper and her team developed COBOL (Common Business-Oriented Language) in the late 1950s, they created something revolutionary: a programming language that business people could actually read. Today, over 65 years later, COBOL still processes an estimated 95% of ATM transactions and 80% of in-person transactions worldwide. Yet for modern development teams, working with COBOL systems presents unique challenges that make data lineage tools absolutely critical.

The Strengths That Made COBOL Legendary

English-Like Readability: COBOL's English-like syntax is self-documenting and nearly self-explanatory, with an emphasis on verbosity and readability. Commands like MOVE CUSTOMER-NAME TO PRINT-LINE or IF ACCOUNT-BALANCE IS GREATER THAN ZERO made business logic transparent to non-programmers, setting it apart from more cryptic languages like FORTRAN. This was revolutionary - before COBOL, business logic looked like assembly language (L 5,CUSTNAME followed by ST 5,PRINTAREA) or early FORTRAN with mathematical notation that business managers couldn't decipher.

Precision Decimal Arithmetic: One of COBOL's biggest strengths is its strong support for large-precision fixed-point decimal calculations, a feature not necessarily native to many traditional programming languages. This capability helped set COBOL apart and drive its adoption by many large financial institutions. This eliminates floating-point errors critical in financial calculations.

Proven Stability and Scale: COBOL's imperative, procedural and (in its newer iterations) object-oriented configuration serves as the foundation for more than 40% of all online banking systems, supports 80% of in-person credit card transactions, handles 95% of all ATM transactions, and powers systems that generate more than USD 3 billion of commerce each day.

The Weaknesses That Challenge Today’s Teams

Excessive Verbosity: COBOL uses over 300 reserved words compared to more succinct languages. What made COBOL readable also made it lengthy, often resulting in monolithic programs that are hard to comprehend as a whole, despite their local readability.

Poor Structured Programming Support: COBOL has been criticized for its poor support for structured programming. The language lacks modern programming concepts like comprehensive object orientation, dynamic memory allocation, and advanced data structures that developers expect today.

Rigid Architecture and Maintenance Issues: By 1984, maintainers of COBOL programs were struggling to deal with "incomprehensible" code, leading to major changes in COBOL-85 to help ease maintenance. The language's structure makes refactoring challenging, with changes cascading unpredictably through interconnected programs.

Limited Standard Library: COBOL lacks a large standard library, specifying only 43 statements, 87 functions, and just one class, limiting built-in functionality compared to modern languages.

Problematic Standardization Journey: While COBOL was standardized by ANSI in 1968, standardization was more aspirational than practical. By 2001, around 300 COBOL dialects had been created, and the 1974 standard's modular structure permitted 104,976 possible variants. COBOL-85 faced significant controversy and wasn't fully compatible with earlier versions, with the ANSI committee receiving over 2,200 mostly negative public responses. Vendor extensions continued to create portability challenges despite formal standards.

The Legacy Challenge: Why COBOL Is Hard to Master Today

The biggest challenge isn't the language itself - it's the development ecosystem and practices that evolved around it from the 1960s through 1990s:

Inconsistent Documentation Standards: Many COBOL systems were built when comprehensive documentation was considered optional rather than essential. Comments were sparse, and business logic was often embedded directly in code without adequate explanation of business context or decision rationale.

Absence of Modern Development Practices: Early COBOL development predated modern version control systems, code review processes, and structured testing methodologies. Understanding how a program evolved - or why specific changes were made - is often impossible without institutional knowledge.

Monolithic Architecture: COBOL applications were typically built as large, interconnected systems where data flows through multiple programs in ways that aren't immediately obvious, making impact analysis extremely difficult.

Proprietary Vendor Extensions: While COBOL had standards, each vendor added extensions and enhancements. IBM's COBOL differs from Unisys COBOL, creating vendor lock-in that complicates understanding and portability.

Lost Institutional Knowledge: The business analysts and programmers who built these systems often retired without transferring their institutional knowledge about why certain design decisions were made, leaving current teams to reverse-engineer business requirements from code.

Why Data Lineage Is Your COBOL Lifeline

This is where modern data lineage tools become invaluable for teams working with COBOL systems:

  • Automated Documentation: Lineage tools can map data flows across hundreds of COBOL programs, creating the documentation that was never written
  • Impact Analysis: Before making changes, teams can see exactly which programs, files, and downstream systems will be affected
  • Business Context: By tracing data from source to consumption, teams can understand the business purpose behind complex COBOL logic
  • Risk Reduction: Visual data flows help prevent the costly mistakes that come from modifying poorly understood legacy systems

The Bottom Line

COBOL's deep embedding in critical business processes represents a significant business challenge and risk that organizations must address. Success with COBOL modernization - whether maintaining, replacing, or transforming these systems - requires treating them as the complex, interconnected ecosystems they are. Data lineage tools provide the missing roadmap that makes COBOL systems understandable and manageable, enabling informed decisions about their future.

The next time you make an online payment, remember: there's probably COBOL code processing your transaction. And somewhere, a development team is using data lineage tools to keep that decades-old code running smoothly in our modern world.

To see and navigate your COBOL code in seconds, call Zengines.

The Biggest Mistakes in Mainframe Modernization

Mistake #1: Underestimating embedded complexity.

Mainframe systems combine complex data formats AND decades of embedded business rules that create a web of interdependent complexity. VSAM files aren't simple databases - they contain redefinitions, multi-view records, and conditional logic that determines data values based on business states. COBOL programs embed business intelligence like customer-type based calculations, regulatory compliance rules, and transaction processing logic that's often undocumented. Teams treating mainframe data like standard files discover painful surprises during migration when they realize the "data" includes decades of business logic scattered throughout conditional statements and 88-level condition names. This complexity extends to testing: converting COBOL business rules and EBCDIC data formats demands extensive validation that most distributed-system testers can't handle without deep mainframe expertise.

Mistake #2: Delaying dependency discovery.

Mainframes feed dozens of systems through complex webs of middleware like WebSphere, CICS Transaction Gateway, Enterprise Service Bus, plus shared utilities, schedulers, and business processes. The costly mistake is waiting too long to thoroughly map all these connections, especially downstream data feeds and consumption patterns. Your data lineage must capture every system consuming mainframe data, from reporting tools to partner integrations, because modernization projects can't go live when teams discover late in development that preserving these data feeds and business process expectations requires extensive rework that wasn't budgeted or planned.

Mistake #3: Tolerating knowledge bottlenecks.

Relying on two or three mainframe experts for a million-line modernization project creates a devastating traffic jam where entire teams sit idle waiting for answers. Around 60% of mainframe specialists are approaching retirement, yet organizations attempt massive COBOL conversions with skeleton crews already stretched thin by daily operations. Your expensive development team, cloud architects, and business analysts become inefficient and underutilized because everything funnels through the same overworked experts.  The business logic embedded in decades-old COBOL programs often exists nowhere else, creating dangerous single points of failure that can derail years of investment and waste millions in team resources.

Mistake #4: Modernizing everything indiscriminately.

Organizations waste enormous effort converting obsolete, duplicate, and inefficient code that should be retired or consolidated instead. Mainframe systems often contain massive amounts of redundant code - programs copied by developers who didn't understand dependencies, inefficient routines that were never optimized, and abandoned utilities that no longer serve any purpose. Research shows that 80% of legacy code hasn't been modified in over 5 years, yet teams spend months refactoring dead applications and duplicate logic that add no business value. The mistake is treating all millions of lines of code equally rather than analyzing which programs actually deliver business functionality. Proper assessment identifies code for retirement, consolidation, or optimization before expensive conversion, dramatically reducing modernization scope and cost.

Mistake #5: Starting without clear business objectives.

Many modernization projects fail because organizations begin with technology solutions rather than business outcomes. Teams focus on "moving to the cloud" or "getting off COBOL" without defining what success looks like in business terms. According to research, 80% of IT modernization efforts fall short of savings targets because they fail to address the right complexity. The costly mistake is launching modernization without stakeholder alignment on specific goals - whether that's reducing operational costs, reducing risk in business continuity, or enabling new capabilities. Projects that start with clear business cases and measurable objectives have significantly higher success rates and can demonstrate ROI that funds subsequent modernization phases.

If you want to avoid these mistakes or need helping overcoming these challenges, reach out to Zengines.

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