9 out of 10 projects become unsupported within 3 years. Here is a system where less code delivers more value, the history itself documents decisions, and entry points by complexity let you choose your level. Own, don't rent.
ORM: model is data. DDD: method+data+memory. Cleaner: method‑data+contract. The model is not data, but the definition of allowed state transitions of that data within an atomic transaction window. Access to the old state is limited to the moment of write lock.
The repository as a knowledge management system: a commit is not a file edit, but an architectural conclusion. Two‑level rebase: turns research chaos into knowledge and places it where it lives by meaning. History is a knowledge tree, not a tracker.
Readability — team discipline: don't spoil history with auto‑formatting, XML docs for abstractions, complex logic — in a method. Master this first: the knowledge tree grows only from clean history.
Exceptions at the top, recursion with a limit, one transaction per use case, lock ordering. This is the foundation: the next material — a model deciding on a commit within the transaction window — rests on this base.