Start with consistent snapshots
A database file is not always a complete copy of an active database. In WAL mode, recent committed changes may be stored in a separate write-ahead log. Use the application’s backup function, SQLite’s backup API or a safely closed and checkpointed source before copying a file into this workbench. Do not delete a live WAL to make the file look simpler.
Keep both originals with meaningful names and record when they were produced. The integrity check tests the supplied snapshot structure; it does not prove that an omitted WAL contained no newer rows. The workbench reports a WAL-mode header when present and keeps the limitation visible for every import.
Understand how row identity is chosen
When both versions declare the same primary-key columns and all observed keys are unique and non-NULL, the comparison aligns rows using those typed values. A matching key with a changed non-key value becomes a changed row. Values are compared with SQLite types preserved, so an integer and a text identifier that look similar are not silently equated.
Some SQLite primary-key declarations permit NULL values, and not every table has a primary key. When a safe key cannot be established, the comparison uses a multiset of complete typed rows. Duplicate counts remain significant. A modified row then appears as a removal plus an addition, because the tool has no reliable evidence that the two records represent the same entity.
Read schema and data changes together
A changed CREATE statement is reported as a schema change. Differences in column layout are handled as complete before/after snapshots rather than a guessed migration. Views, indexes and triggers appear in schema evidence, while virtual-table content is outside the data comparison. Review the full comparison JSON for details beyond the summary counts.
The tool never applies an update to either source. If the comparison is used to design a migration, develop and test that migration separately against disposable backups. A row diff does not determine the business meaning of a change or whether it should be accepted. Preserve the snapshot evidence alongside your review notes.