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    CASE STUDY · SAP MODERNISATION · ENTERPRISE · NETHERLANDS

    A Dutch Enterprise Moves SAP ECC to S/4HANA

    A Netherlands-based enterprise engaged Syntra ETL to support its transformation from SAP ECC to SAP S/4HANA. Syntra ETL supported the end-to-end migration lifecycle — ECC extraction, source-to-target mapping, transformation and cleansing, validation, migration-cycle execution, exception management and reconciliation — before business-critical data was loaded into the new S/4HANA environment.

    SAP ECC
    Source platform
    SAP S/4HANA
    Target platform
    Multi-cycle
    Controlled migration cycles
    Netherlands
    Enterprise programme

    The challenge: SAP to SAP is not a copy

    It is tempting to assume that moving from ECC to S/4HANA is simpler than moving to a different vendor, because both ends are SAP. In data terms that is the wrong intuition. S/4HANA changed the underlying model in ways that make several ECC structures unrecognisable in the target, and those changes are mandatory rather than optional.

    The work on this programme was addressing exactly those differences between legacy ECC structures and the S/4HANA target model, while preserving data quality, relationships and business integrity through the transition.

    The other half of the problem is confidence. A cutover to a new core ERP is a one-way door for most organisations, so the programme needed visibility into data-quality and reconciliation issues well before the production window — which is what repeatable migration cycles exist to provide.

    Challenges we solved

    The structural differences between ECC and S/4HANA drive most of the data work on a conversion.

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    A changed target model

    Legacy ECC structures do not map one-to-one onto S/4HANA. The differences were addressed explicitly in mapping and transformation rather than discovered during load.

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    Preserving relationships

    Data relationships and business integrity had to survive the transition, so records arrived in S/4HANA connected and usable rather than as isolated rows.

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    Quality before cutover

    Transformation and cleansing ran inside the pipeline, so data quality improved with each cycle instead of being remediated under cutover pressure.

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    Repeatable migration cycles

    The structured approach enabled multiple controlled cycles, each one a full rehearsal rather than a partial test.

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    Controlled exception resolution

    Exceptions were managed as a defined step with reporting per cycle, so resolution was tracked and carried forward rather than repeated.

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    Visibility ahead of go-live

    Data-quality and reconciliation issues were surfaced ahead of production cutover, which is where confidence in a one-way migration actually comes from.

    The migration lifecycle

    The full lifecycle, executed as repeatable cycles so the production cutover was a rehearsed step rather than a first attempt.

    SAP ECCExtractMapTransform & cleanseValidateMigration cycle executionException managementReconcileS/4HANA

    What the engagement covered

    The team supported the end-to-end migration lifecycle rather than a single stage of it.

    Extraction

    • SAP ECC data extraction
    • Repeatable across migration cycles
    • Business-critical data in scope

    Mapping

    • Source-to-target mapping
    • Addressing ECC to S/4HANA model differences
    • Mapping carried consistently across cycles

    Transformation & cleansing

    • Data transformation to the S/4HANA model
    • Cleansing inside the pipeline
    • Preserving relationships and business integrity

    Validation

    • Validation ahead of load
    • Data-quality visibility per cycle
    • Issues surfaced before cutover

    Cycle execution

    • Multiple controlled migration cycles
    • Each cycle a full rehearsal
    • Production readiness established before cutover

    Exception management & reconciliation

    • Controlled exception resolution
    • Reconciliation before loading to S/4HANA
    • Confidence in the production cutover

    What actually changes between ECC and S/4HANA

    These are the structural changes that create the data work on a conversion. They are mandatory, not configuration choices, which is why an SAP-to-SAP move is not a copy.

    ACDOCA — the Universal JournalS/4HANA merges finance and controlling into a single line-item table. The separate FI and CO structures and their aggregate tables that ECC reporting was built on are replaced, so anything reading those structures has to be re-pointed and any reconciliation built on them has to be rebuilt.
    Business Partner — mandatoryCustomers and vendors become a single Business Partner object through Customer/Vendor Integration. This is not optional in S/4HANA, and it is where most conversions find their master-data problems: duplicate parties, number-range collisions between customer and vendor ranges, and records that were never clean enough to merge.
    Index and aggregate tables removedThe secondary index and aggregate tables that ECC maintained for open and cleared items are gone, replaced by views computed on the fly. Custom code and extracts that read them directly have to be found and changed.
    MATDOC — inventory managementMaterial document and stock aggregate structures are consolidated. Stock quantities are derived rather than stored in the ECC aggregates, which changes how inventory positions are extracted and reconciled.
    Material number field lengthThe material number field was extended beyond its ECC length. Interfaces, custom code and any downstream system that assumed the old width need checking — a truncation here is silent and permanent.
    Brownfield, greenfield or selectiveA system conversion carries the existing system forward; a new implementation rebuilds and migrates selected data; a selective transition takes parts of both. The choice determines the entire data scope, and it is a business decision made before any mapping work begins.

    How a controlled S/4HANA data migration runs

    The sequence below is what makes a cutover rehearsed rather than attempted. Each cycle runs the whole thing, not a sample.

    1. 1Establish the conversion approachBrownfield, greenfield or selective. Everything downstream — scope, mapping, how much history moves — follows from this, so it is settled first.
    2. 2Profile the ECC sourceFind the duplicates, the orphans, the dormant custom tables and the master data that will not survive Business Partner conversion. This is where a conversion is won or lost.
    3. 3Resolve master data before conversionCustomer and vendor records are de-duplicated and cleansed ahead of Business Partner conversion, because merging bad data produces a worse target, not a clean one.
    4. 4Map source to targetExplicit mapping for the structures that changed, held in a workbook, reviewed with the business and applied identically in every cycle.
    5. 5Transform and cleanse in the pipelineCorrections applied as repeatable rules, so a fix made in cycle one is still applied in cycle three without anyone remembering to do it.
    6. 6Validate before loadStructural and business-rule validation on prepared data, so problems surface as reportable exceptions instead of failed loads in the target.
    7. 7Execute the migration cycleA full load into the S/4HANA target, not a subset — a partial rehearsal proves very little about a full cutover.
    8. 8Reconcile and resolve exceptionsReconciliation per cycle with exceptions categorised and carried into the next run, so each cycle starts from a shorter list than the last.
    9. 9Confirm production readinessThe final rehearsal should closely replicate the production cutover. When it does, readiness is demonstrated rather than assumed.

    Business Partner conversion is the item that most often surprises an ECC to S/4HANA programme. It is mandatory, it exposes every historic duplicate between the customer and vendor masters, and it cannot be deferred past cutover — which is why master data is cleansed before conversion rather than after.

    Key outcomes

    What the programme delivered.

    Successful transition of critical SAP data to S/4HANA.
    Streamlined transformation and validation across the migration lifecycle.
    Reduced manual migration effort.
    Improved data quality ahead of cutover.
    Controlled exception resolution rather than informal correction.
    Greater confidence in the production cutover through repeatable migration cycles.
    Indicative planning ranges

    Sizing an S/4HANA conversion at enterprise scale

    A sense of scale before discovery, for teams planning a comparable conversion. The ranges below are what an ECC estate at roughly $2bn revenue typically carries into an S/4HANA programme.

    Employees3,000 – 10,000
    Company codes10 – 50
    G/L accounts2,000 – 8,000
    Cost centres / profit centres500 – 3,000
    Customer + vendor records into Business Partner15,000 – 150,000
    Expected duplicate rate at BP conversion3% – 15%
    Material master records50,000 – 500,000
    FI/CO line items per year5M – 50M
    Open items at cutover20,000 – 200,000
    Years of history in scope2 – 10
    ECC database size1 – 10 TB
    Typical programme duration12 – 24 months
    Full migration rehearsal cycles2 – 4

    These are planning ranges, not this customer's figures. They are typical planning ranges for an enterprise of roughly this size, published to help you size your own conversion. Actual scope is established during discovery, and the conversion approach — brownfield, greenfield or selective — changes several of these figures substantially.

    Frequently asked questions

    What is involved in an SAP ECC to S/4HANA data migration?
    Extraction from ECC, source-to-target mapping that addresses the structural differences between the two models, transformation and cleansing, validation, execution across controlled migration cycles, exception management and reconciliation before business-critical data is loaded into S/4HANA.
    Is ECC to S/4HANA easier than migrating to a different ERP?
    Not in data terms. S/4HANA changed parts of the underlying model in ways that are mandatory rather than optional, so several ECC structures do not carry across unchanged. The work is different from a cross-vendor migration, not smaller.
    Why run multiple migration cycles before an S/4HANA cutover?
    Because a core ERP cutover is effectively a one-way door. Repeatable cycles surface data-quality and reconciliation issues while there is still time to fix them, and establish production readiness on evidence rather than expectation.
    How is business-critical data validated before it reaches S/4HANA?
    Validation runs on the prepared data ahead of each load, so structural and business-rule problems surface as reportable exceptions rather than as failures inside the target. Exceptions are categorised per cycle and carried forward, so each run starts from a shorter list than the last.
    How is data quality improved before an S/4HANA go-live?
    Transformation and cleansing run inside the migration pipeline and validation runs ahead of each load, so quality improves cycle over cycle instead of being remediated under cutover pressure.
    What is the Universal Journal and why does it matter for migration?
    S/4HANA merges finance and controlling into a single line-item table, replacing the separate FI and CO structures and aggregate tables that ECC reporting relied on. Anything that read those structures — including existing reconciliation and custom reports — has to be rebuilt against the new model.
    Why is Business Partner conversion the hard part of an S/4HANA migration?
    Because it is mandatory and it merges two master data sets that were never maintained to be merged. Duplicate parties, number-range collisions between customer and vendor ranges, and records that were tolerable in isolation all surface at once. Cleansing has to happen before conversion, not after.
    What is the difference between brownfield, greenfield and selective data transition?
    A brownfield system conversion carries the existing system forward. A greenfield implementation rebuilds and migrates only selected data. A selective transition takes elements of both. The choice sets the entire data scope, so it is made before mapping starts.
    How many migration cycles does an S/4HANA conversion need?
    Enough that the last one closely replicates the production cutover — commonly two to four full cycles. Each should be a complete load rather than a sample, because a partial rehearsal proves very little about a full cutover.

    Planning an S/4HANA conversion?

    Tell us your ECC release, the modules in scope, how much history has to move and your target cutover date.