Migrating from Oracle EBS to SAP S/4HANA: Strategic Architecture and Feasibility Roadmap

Planning a migration from Oracle to SAP S/4HANA? Explore our 2026 guide on feasibility, architectural transition, TCO analysis, and the Clean Core strategy.

Many companies still run finance, supply chain, and manufacturing on Oracle E-Business Suite. The system works, but every change costs more than it should. Reporting depends on reconciliations. Custom PL/SQL logic lives in places no one wants to touch. But is it still reasonable to extend Oracle EBS, or is it time to replace it?

SAP S/4HANA often appears to be the logical replacement. Still, the hesitation is real. Will historical financial data survive the move? What happens to years of Oracle custom logic? Is this a clean rebuild, a partial transition, or a controlled reuse of what already works? A wrong decision here does not slow a project: it creates years of operational debt.

This article walks through how to approach an Oracle EBS to SAP S/4HANA transition. You will see how feasibility is assessed, how target architecture is defined for the 2026 SAP reality, how data and custom code are handled, and how cost compares over time. The goal is simple: it will help you decide whether the move makes sense. If it does, it will help you plan it without damaging business continuity. Keep reading. 

Why SAP S/4HANA — and Why 2026 Changes the Equation

The decision to move away from Oracle E-Business Suite is rarely triggered by a single event. It usually starts with accumulated friction.

Oracle EBS continues to run critical processes, but day-to-day work becomes heavier over time. Reporting cycles extend. Custom changes take longer to test and deploy. Integrations rely on reconciliations outside the system. In 2026, these are no longer minor inefficiencies. They affect audit readiness, compliance control, and the ability to automate finance and supply chain operations.

This leads to a practical question: can the current system support another decade of regulatory pressure, automation demands, and data volume growth? For many organizations, the answer is uncertain. That uncertainty is what pushes SAP S/4HANA into the discussion.

Among large-scale ERP platforms, SAP S/4HANA is considered because it changes how financial and operational data is stored and processed, not because it replaces Oracle feature by feature. Its design removes several structural limitations that exist in Oracle EBS, especially in finance. This difference matters when companies look for fewer reconciliations, consistent reporting, and a stable base for automation.

Where Oracle EBS starts to limit change

Oracle EBS was built to grow through modules and extensions. Over the years, this resulted in separated sub-ledgers, duplicated financial tables, and large volumes of PL/SQL code spread across reports, forms, interfaces, and batch jobs. A single change in a finance process often affects several technical layers at once.

Three constraints appear most often:

1. First, financial data is distributed across multiple tables. Reconciliation between ledgers becomes a recurring task, which extends the period close.
2. Second, custom PL/SQL logic is tightly coupled to the Oracle database structure. Even small functional changes require code adjustments, testing cycles, and database-level expertise.
3. Third, reporting depends on extracts or summary tables. Business users rarely work with the same data used for posting, which introduces timing differences and control risks.

SAP S/4HANA approaches these issues through a simplified financial data model. The Universal Journal (ACDOCA) stores general ledger, asset accounting, and management accounting entries in a single table. This reduces ledger reconciliation work and removes several aggregation steps. Reporting tools access the same records used for posting, without separate data preparation layers.

This is the point where migration choices become decisive. Copying Oracle structures and logic into SAP keeps the same constraints in place. Redesigning finance and logistics processes allows the S/4HANA data model to work as intended.

This is why migration should be treated as a process redesign, not as data transport. Industry studies, including PwC’s S/4HANA journey analysis, show that 70% of migration benefits are lost when legacy processes are moved without change.

Regional factors that influence migration priorities

Although the target platform is the same, the reasons for migration vary by region. These differences affect scope, sequencing, and architectural decisions.

• In North America, organizations often focus on finance automation and planning accuracy. Typical goals include shorter close cycles, automated accruals, and forecasting based on current transactional data.
• In Europe, compliance requirements dominate planning. Data handling must meet GDPR standards, and AI usage must align with the EU AI Act. Additionally, sustainability reporting increasingly depends on finance-grade data captured directly in the ERP system.
• In Latin America, ERP modernization often supports expansion. Integration with local payment platforms, tax engines, and fast-growing production environments shapes system design.
• In the Asia-Pacific, especially in Southeast Asia, manufacturing automation is a key driver. ERP systems must process high transaction volumes and integrate with sensor-driven shop floors without relying on overnight batch windows.

These differences explain why there is no universal migration template. The same SAP S/4HANA platform supports different priorities, depending on regulatory, operational, and industry context.

Regional Drivers at a Glance

What to Check Before Committing to an Oracle-to-SAP Migration

Before approving a migration program, most organizations focus on timelines and cost. Technical feasibility often comes later, when decisions are harder to reverse. This is risky. An Oracle-to-SAP transition succeeds or fails long before the first data load, based on how custom code, data structures, and processes are handled.

This section explains the technical factors that determine whether a migration can scale, remain supportable, and align with SAP’s current architectural standards. The focus is not on tooling alone, but on how technical choices affect long-term system stability.

Technical debt as the main constraint

In Oracle E-Business Suite landscapes, technical debt is rarely visible at first glance. It accumulates over years of extensions and local fixes. Custom PL/SQL packages replace standard logic. Database triggers handle business rules. Reports and interfaces depend on specific table layouts.

This level of customization limits migration options. Every custom object must be reviewed, rewritten, or replaced. More importantly, uncontrolled custom code conflicts with SAP’s Clean Core principle, which aims to keep the S/4HANA core system free from direct modifications.

Clean Core is not a design preference: it is a support requirement. SAP updates, security patches, and cloud operations depend on it. Ignoring this principle increases future upgrade effort and reduces system stability.

Reviewing Oracle customizations before the move

Oracle customizations are commonly grouped under CEMLI: configuration, extensions, modifications, localizations, and integrations. Each category has a different migration path.

Some configurations map directly to SAP standard settings. Others must be redesigned, because the underlying process model is different. Modifications and extensions require the most attention, as they often embed business rules deep inside the database.

In SAP projects, custom logic is typically moved outside the core system. Side-by-side extensions run on SAP Business Technology Platform, while the S/4HANA system remains close to standard. This separation allows custom development without blocking upgrades or support.

This is also where early process analysis matters. Using process mining tools before migration helps identify how Oracle workflows actually run in production. This prevents rebuilding outdated or unused logic and supports a realistic Fit-to-Standard assessment.

Where AI helps and where it does not

Custom code conversion is one of the most time-consuming parts of an Oracle-to-SAP migration. Manual rewriting of PL/SQL procedures, triggers, and reports into ABAP or HANA SQL requires both functional and technical knowledge.

Generative AI can assist in this step, but only as an accelerator. At LeverX, AI models trained on Oracle PL/SQL and SAP ABAP are used to support initial refactoring. They help convert syntax, identify patterns, and suggest equivalent structures for HANA-based execution.

This approach can reduce manual effort for routine conversions. It does not replace expert review. Converted logic must still be validated, optimized for in-memory processing, and aligned with SAP security and performance standards. AI shortens preparation time, but human expertise determines correctness.

Mapping data structures from Oracle to SAP

One of the most critical technical phases is the structural mapping of organizational units. Oracle and SAP use different concepts to represent legal, financial, and operational boundaries.

In Oracle EBS, Sets of Books define accounting scope and currency. Operating Units control transactions across finance and logistics. Flexfields store descriptive attributes with minimal structure.

In SAP S/4HANA, Company Codes represent legal entities. Sales Organizations and Plants define commercial and logistical boundaries. Data attributes are stored in predefined or explicitly extended fields with clear data types.

Incorrect mapping at this stage creates downstream issues in reporting, consolidation, and compliance. This is why data object mapping must be validated before migration tooling is selected or development begins.

Choosing the Right Path for Your Migration

Once feasibility is confirmed, the next decision defines the entire program: where SAP S/4HANA will run and how much flexibility the architecture allows. This choice affects cost, scope, customization strategy, and long-term maintenance.

SAP offers two main paths: RISE with SAP and GROW with SAP. In Oracle-to-SAP programs, there is also a third option that combines SAP with selected legacy components. Each approach fits a different level of complexity and risk tolerance.

RISE with SAP: Private Cloud for complex Oracle landscapes

RISE with SAP is typically selected by organizations with large Oracle EBS environments and long customization histories. These systems often support multiple legal entities, complex tax structures, and industry-specific processes.

In a RISE setup, SAP S/4HANA runs in a private cloud environment, allowing more control over system configuration and a wider range of functional scope than public cloud editions. For Oracle migrations, this matters when custom processes cannot be fully replaced by standard SAP behavior in the first phase.

RISE is often chosen when business continuity is a priority. It supports phased transitions, selective data moves, and controlled reuse of existing logic, while still aligning with SAP’s cloud operations model.

GROW with SAP: Public Cloud and a standardized restart

GROW with SAP is designed for companies that want a clean restart. It is commonly used by subsidiaries, regional units, or mid-sized organizations that can operate with standard processes.

In this model, SAP S/4HANA runs as a public cloud service with predefined scope. Custom development is limited. Process design follows SAP best practices by default. For former Oracle users, this means accepting structural change upfront in exchange for faster deployment and simpler operations.

GROW works best when the Oracle system has limited customization or when the goal is to retire legacy logic rather than replace it. It is less suited for environments that rely on deep database-level custom code.

Hybrid architecture: moving the core, keeping the exceptions

Some organizations choose a hybrid approach. Core finance and logistics move to SAP S/4HANA, while selected Oracle-based components remain in place for a defined period. This is common for niche HR functions, local payroll, or country-specific solutions that are too costly to replace immediately.

A hybrid setup reduces risk by narrowing the initial migration scope. It also requires clear boundaries between systems and strong data governance to avoid duplication and inconsistencies. This approach works best as a transition state, not a permanent design.

But data still defines the outcome

Whichever path you choose, data must move. Historical balances, open transactions, and master records define whether the new system can operate correctly from day one. Industry research, including Deloitte’s data-first approach, consistently shows that data handling is the highest-risk part of ERP transitions.

At LeverX, data preparation is handled through DataLark, a platform designed to extract, standardize, and validate Oracle EBS data before it is loaded into SAP S/4HANA. This step focuses on structure, consistency, and audit readiness, not just transfer speed. The goal is to ensure that data supports financial reporting and control once it reaches the Universal Journal.

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Inside the Oracle-to-SAP Transition Process

After architecture decisions are made, the focus shifts to execution. This is where many programs lose control. Oracle-to-SAP migrations fail not because of a single mistake, but because technical work starts before the system is fully understood.

A structured migration process reduces this risk. The goal is not speed, but accuracy, continuity, and a system that remains supportable after go-live. In practice, this means breaking the transition into clear phases, each with its own technical checkpoints.

Phase 1: System assessment and migration planning

The first phase focuses on understanding the current Oracle EBS landscape in detail. No code or data is moved at this stage.

The work starts with a technical and functional inventory. All custom objects are identified and classified, including configurations, extensions, database modifications, local logic, and external connections. This step defines which elements can be retired, which must be rebuilt, and which can be replaced with SAP standard functionality.

Process analysis follows. Instead of relying only on workshops, data-based analysis is used to review how processes actually run in production. Transaction paths, exceptions, and manual workarounds become visible. This prevents rebuilding unused or outdated logic in the target system.

Based on this analysis, the migration strategy is selected:

• A greenfield approach fits organizations ready to redesign processes from scratch.
• A brownfield approach focuses on technical conversion with minimal change.
• Selective data transition fits large, complex Oracle environments that require control over scope, history, and timing.

Phase 2: Data transition and core build

Once the strategy is set, execution begins with data.

For Oracle EBS migrations, selective data transition is often the most stable option. Instead of moving the full historical database, only relevant and active data is transferred to SAP S/4HANA. This usually includes recent fiscal years, open transactions, and required master data.

Historical records that are no longer operational are archived separately with read-only access. This reduces SAP HANA data volume and keeps financial history available for audit and reference, without increasing system load.

Data preparation is handled outside the SAP core. At LeverX, this is done using DataLark to extract, clean, standardize, and validate Oracle data before loading. This approach supports Clean Core principles and reduces reconciliation effort during testing.

At the same time, the SAP S/4HANA core system is configured. Custom logic is developed outside the core system where required, following side-by-side design patterns. This keeps the core system stable and update-ready.

Phase 3: Validation and controlled testing

Testing in Oracle-to-SAP programs must go beyond basic functionality checks.

Financial validation is a priority. Automated reconciliation compares Oracle balances with SAP postings at the company code and currency level. Differences are analyzed and resolved before user testing begins.

Performance testing follows. Load scenarios simulate peak transaction volumes, period close activity, and reporting demand. This step is critical when moving from disk-based Oracle databases to in-memory processing.

User acceptance testing focuses on daily operations. Users validate finance, logistics, and reporting flows in the SAP Fiori interface. The goal is not interface familiarity, but task completion accuracy and timing.

Phase 4: Go-live and post-migration support

For large or global organizations, a single global cutover is rarely the safest option.

A phased rollout reduces operational risk. Regions or business units go live in controlled waves, allowing lessons learned to be applied to the next deployment. This approach also limits disruption to finance and supply chain operations.

After go-live, close monitoring is required. Transaction errors, performance issues, and data inconsistencies are addressed immediately. Early stabilization focuses on financial closing, order processing, and reporting reliability.

Support during this period is structured and time-bound. The objective is to transfer system ownership to internal teams once processes stabilize.

Migration Approach Comparison

What Does the Move Mean for Cost and Long-Term Value?

Technology decisions around ERP are often framed as transformation initiatives. In practice, they are cost and risk decisions. By 2026, many organizations have already found that the cost of keeping Oracle E-Business Suite operational increases faster than expected, even without major functional changes.

SAP S/4HANA changes this cost structure, but only when the move is planned correctly.

Oracle EBS vs. SAP S/4HANA: Cost drivers in practice

The difference is not limited to licenses. It shows up in daily operations.

Oracle EBS typically involves:

• Ongoing hardware and database maintenance
• High dependency on custom PL/SQL skills
• Separate data structures that require reconciliation
• Reporting delays caused by data extracts

SAP S/4HANA typically shifts costs toward:

• Subscription-based infrastructure under RISE or GROW
• Reduced data volume through simplified financial tables
• Fewer reconciliation steps in finance
• Reporting based on live transactional data

Many programs report a noticeable reduction in data footprint after migration, by up to 20–30%. Actual results depend on data scope, archiving strategy, and process redesign choices.

Practical recommendations before you commit

Some decisions have a direct impact on both cost and stability.

1. Clean the data before moving it.
   Migration is the best time to fix years of duplicated, incomplete, or unused records. Moving poor-quality data only transfers the problem to a new system.
2. Protect the SAP core from day one.
   Rebuilding Oracle custom logic inside S/4HANA increases future upgrade effort. Side-by-side extensions reduce long-term maintenance pressure.
3. Prepare users for a new way of working.
   The move from Oracle Forms to SAP Fiori affects daily routines. Training and role-based testing reduce resistance and post-go-live issues.

How LeverX Supports the Transition

Moving from Oracle EBS to SAP S/4HANA is a rational decision. Companies do it to simplify finance, reduce long-term maintenance, and regain control over data and processes. When done properly, it is rarely a decision anyone regrets.

The frustration usually comes from execution. So many things can go wrong and lead to unexpected headaches.

At LeverX, we help to carry out the Oracle-to-SAP transition with a clear plan, clean data, and realistic expectations. We understand how Oracle systems are built, how SAP S/4HANA behaves under real business load, and how to connect the two without overcomplicating the result.

Our role is simple:

• Help you choose the right migration path
• Avoid unnecessary rework and technical dead ends
• Make sure the new system feels like progress.

If you’re interested in SAP S/4HANA and want clarity on what the move would look like in your specific case, let’s talk. A short conversation can save months of uncertainty later. Book a free consultation now.