Learning Objectives
By the end of this lesson you will be able to:
- Apply the software selection framework to a realistic migration scenario
- Identify the tool selection considerations specific to a multi-system ERP migration
- Explain how the tool selection interacts with the supplier engagement and DMZ
The DHGS Software Challenge
Deep Hole Gravel Services is migrating from seven or more legacy systems - covering equipment, vehicles, finance, HR, sales, CRM, and departmental spreadsheets - onto a single ERP platform.
The migration involves:
- Multiple source systems with different database platforms and data formats
- Complex transformations, particularly for Equipment and Customer data
- A phased migration approach (Customer data first, Equipment data later)
- A substantial DQR workload (hundreds of DQR items expected)
- A medium-scale programme (millions of records, not billions)
Assessment Against Selection Criteria
Scale: Medium. The Finance system and CRM together hold the largest volumes. Equipment and Work Register data is complex but not extremely voluminous. A general-purpose ETL tool or a well-structured scripting approach would both handle the scale.
Budget: Mid-range. DHGS is not a large enterprise - licensing costs for a top-tier ETL tool may be disproportionate. A mid-range ETL tool or a well-managed scripting approach is more appropriate.
Migration Form: Phased. The ETL must support sequential migrations of different KBDAs with independent staging areas for each phase.
Local Policies: The ERP vendor has a preferred migration toolset. This is a legitimate consideration but must be assessed for fit - particularly for the non-standard legacy systems (Kelsey Pit, departmental spreadsheets) that the vendor’s migration toolset was not designed to handle.
Resource: The supplier has skills in the ERP vendor’s migration toolset. There is limited internal DHGS technical capability.
Recommended Approach
For DHGS, the recommended approach combines:
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ERP vendor migration tools for the data that maps cleanly to standard ERP entities (Finance ledger data, standard HR data, standard Customer master data)
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Custom scripting (Python/SQL) for the complex, non-standard data: Kelsey Pit equipment records, Work Register data, vehicle fleet data. These require complex transformation logic that the vendor tool does not handle well.
-
Data quality tool (or structured DQR spreadsheets for this scale) for deduplication of Customer and Product data before migration.
This hybrid approach uses the supplier’s preferred tool for the standard work, reduces risk on the complex data by using flexible scripting, and keeps costs proportionate to the programme scale.
DMZ and Software Implications
Under the DHGS contract:
- The supplier is responsible for the ERP vendor migration toolset and the standard data migrations
- The client PDM team (with the Migration Analyst) manages the DQR process and the custom scripting for non-standard data
- Data exchange across the DMZ uses agreed file formats deposited to a shared staging environment
The DMZ document specifies the format and frequency of data exchange, the validation that must occur on each side before data crosses the boundary, and the commercial treatment of issues that arise.
Lessons from the DHGS Case
The vendor tool gap: The ERP vendor’s migration toolset was not designed for the Kelsey Pit data structure. Using it would have required extensive customisation - potentially more expensive than building the custom scripts. The hybrid approach was identified early in the MSG process.
Resource planning: DHGS’s internal team did not have ETL tool skills. The decision to use SQL/Python scripting for the non-standard work was in part driven by the availability of SQL skills within the team, reducing dependency on the supplier.
DQR quantification: The data quality tool was used primarily to run initial profiles across all seven legacy systems in parallel - the fastest way to produce the DQR item count and priority distribution that the DQR Board needed to start planning.
Key Takeaways
- Multi-system ERP migrations rarely have a single tool that covers all scenarios - hybrid approaches are common
- The ERP vendor’s tool handles standard data well but may be inadequate for complex, non-standard legacy systems
- DMZ design must account for the software architecture - tool-by-tool data flow should be specified in the DMZ
- Resource planning for tool skills is part of the MSG; hidden dependency on supplier skills is a programme risk
Final module: 08.01 - Introducing DHGS