4 posts filed under schema.
MongrelDB allows one primary key column per table by design, so a composite natural key like (tenant_id, slug) is modeled as a multi-column unique constraint enforced atomically at commit, with an optional surrogate auto-increment key when you need a point-lookup handle.
MongrelDB Kit stamps every applied migration with a content-aware SHA-256 checksum over its recorded intent and re-verifies it on every run, so editing a historical migration after it shipped fails loudly at the next deploy instead of silently re-shaping production.
MongrelDB Kit's typed schema DSL and its raw SQL surface are two front doors to the same engine rather than one compiling into the other, and knowing which door to use, and how to mix both inside a single migration, is most of the skill.
The MongrelDB PHP client treats schema as typed data instead of SQL strings, so the same call that creates a table can be paired with a catalog read that proves the server stored what you think it stored.
