A concrete data modeling blueprint for construction ERP systems that need traceable cost flow from BOQ to PO to invoice.
Why generic ERP schemas fail in construction
Construction projects require change-order traceability, project-specific cost coding, and procurement constraints that generic schemas often miss.
Entity relationship flow
Diagram (Mermaid)
Required fields by stage
- BOQ item: work package, unit, quantity baseline, revision
- purchase request: cost code, required date, approving authority
- PO line: tax class, contractual terms, delivery location
- invoice line: receipt reference, retention, variance reason
Constraint rules
- every PO line must map to one approved budget line
- invoice variance over threshold requires dual approval
- retroactive edits are blocked; changes use revision records
Migration checklist for legacy ERP
- map old cost codes to normalized chart
- preserve original references for audit back-trace
- backfill receipts and invoice links before go-live
- run variance reconciliation for last 12 months
Final takeaway
A reliable construction ERP starts from cost traceability, not screens. Get the data model right first.
