In reading order.
Rename a property, change a type, ship the release - and every payload you stored last year stops deserialising. Introducing VersionKit, a .NET library that declares schema history as attributes and migrates old data on read.
Rename, move, add, remove, type change - VersionKit's attribute surface covers five kinds of schema evolution. This part walks the whole declarative API, the merge rules behind stacked attributes, and what the attributes deliberately refuse to express. Part 2 of the Entity Versioning with VersionKit series.
At startup VersionKit reflects over your model assembly and compiles property attributes into an executable pipeline - one migration step per version pair, five operation types, all of them deliberately idempotent. Part 3 of the Entity Versioning with VersionKit series.
Every stored payload carries a __version stamp; every read walks it up one step at a time. This part dissects VersionKit's lazy migration pipeline - the MigrationRunner API, the JsonElement traps System.Text.Json sets for dictionary code, and reading history on purpose. Part 4 of the Entity Versioning with VersionKit series.
Splitting a name field, converting a string to a bool, deriving a flag from a total - some migrations are code, not metadata. This part covers VersionKit's three escape hatches and the sharp edges each one carries. Part 5 of the Entity Versioning with VersionKit series.
Lazy migration makes deploys instant but taxes every read of old data. VersionKit's backfill service rewrites stale payloads in scheduled batches until the store converges on the current version - in a host, or from a serverless function. Part 6 of the Entity Versioning with VersionKit series.
JSON payloads can migrate lazily because the reader controls the shape - relational rows cannot, because the table is the shape. VersionKit's EF Core answer is table-per-version - archive Orders as Orders_v2 on a schema bump, track every row's home in a registry, and let old rows stay old until something moves them. Part 7 of the Entity Versioning with VersionKit series.
A point lookup that might hit any of three tables, a list query that should span them all, and writes that must keep a registry honest - this part walks VersionKit's version-aware reader and writer, and the generated UNION view that makes every schema era queryable as if it were current. Part 8 of the Entity Versioning with VersionKit series.
Archive tables are meant to empty out - a background worker migrates their rows into the current table while live traffic reads and write-through updates race it. This part walks the EF backfill's insert-then-conditional-delete choreography and the timestamp that keeps it honest. Part 9 of the Entity Versioning with VersionKit series.
Static registries, Activator-created migrators, a Postgres accent, a flag that does nothing, and no test project - the closing part of the VersionKit series itemises every trade-off in the library, says when you should not use it, and sketches what comes next. Part 10 of the Entity Versioning with VersionKit series.
