SqliteSchemaMigration

Non-destructive schema migration shared by every SQLite database in the SDK.

SDK updates (and rollbacks to a version that already has this migration) keep the data in every SDK database: the unsent upload queue, the map cache, the user's favourites and recently viewed places, location-marketing campaign state, property metadata, diagnostics and map overlays.

How it works, per database: the version is a constant LEGACY_VERSION_CODE_CEILING + revision that changes only when a table's CREATE SQL changes, and onUpgrade/onDowngrade call reconcileColumns for each table (rows kept) and then onCreate (CREATE TABLE IF NOT EXISTS for any table that was missing).