Consider the user input before proceeding (if not empty).
-
Determine scope — from user input, or ask:
a. What is the source system? (name, type, rough record count)
b. What data must be migrated? (all / subset by date / subset by
entity)
c. Is downtime acceptable? (yes / no / limited window)
-
Interactive questionnaire (interactive mode only):
a. Source system type: A) relational DB, B) file system / CSV,
C) another SaaS, D) mix.
b. Record volume: A) < 100K, B) 100K–1M, C) 1M–100M, D) > 100M.
c. Migration strategy preference (see table above).
d. Cutover window: A) weekend maintenance, B) overnight weekday,
C) business hours with parallel run, D) not decided.
e. Rollback trigger: A) any reconciliation failure, B) > X%
failure rate, C) manual decision only.
f. Privacy / compliance: does the migrated data contain PII,
financial data, or health records? (affects encryption and
audit requirements).
-
Draft field mapping — for each target entity in the data
model, map source fields to target fields, noting:
- Data type transformation needed (e.g. VARCHAR → UUID)
- Nullable / required differences
- Default value for missing source data
- Transformation rule (concatenate, split, lookup, generate)
Mark unmapped fields as DMDEBT entries.
-
Define data quality rules:
- Null handling policy per critical field
- Duplicate detection strategy
- Character encoding (UTF-8 requirement)
- Date / time zone normalisation
- Referential integrity checks
-
Outline ETL process (logical, not code):
- Extract: source query / export mechanism, incremental vs full
- Transform: rule application order, error handling
- Load: batch size, idempotency strategy, index rebuild
- Verify: record count match, sample spot-checks, checksum
-
Define cutover plan:
- Freeze point (when writes to old system stop)
- Migration window duration estimate
- Rollback decision point and trigger
- Communication plan for downtime
-
Draft migration runbook — step-by-step numbered procedures
for the cutover team, including go / no-go decision checkpoints.
-
Post-migration validation checklist — items the team must
verify within 24 h of cutover before decommissioning the source.
-
Write outputs — write plan, field mapping, runbook, and
extract.
-
Summary — print strategy, estimated cutover window,
unmapped field count (DMDEBT), and recommended next action.