Task. Move a database to PostgreSQL in a way the owner can check for themselves: every row and every cent is there, and a report shows it.
Solution. Structure and data move in one transaction, so a failure rolls everything back and never leaves half a database. The old database is opened read-only. A verification report then compares both sides table by table: row counts and a checksum of every value, per-column checks (empty values, sums, text length, date ranges), foreign keys validated on every row, indexes and key sequences.
Delivered. 11 tables, 15,607 rows, 11 foreign keys and 10 indexes, all matching. The report was tested too. The data was damaged in six ways (one cent in a total, a lost row, one changed letter, a date off by a second, an extra row, a reset key sequence), and each time the report named the table and showed the first row that differs. It opens in a browser or on a phone and prints to PDF.
Demo on the open Chinook sample database (MIT licence); no client. On a real project the first stage is a test migration of your database with this report, before anything changes on the live system.
