Show HN: Denorm – Declarative derived columns (Postgres)

Denorm solves my own long-standing pain points with biz logic and the DB, providing a declarative DSL in which derived columns are part of the schema. Data moves along foreign keys: down from parent to child, aggregate from child to parent, and of course within rows. Can also generate parents and children along the foreign key.

The README example:

  table us_states
    column state_code char(2) primary key
    column state_name varchar(20)
    column children_count integer count child_table

  table child_table
    column child_id serial primary key

    fk us_states references us_states pushes child_table
    column state_code is us_states.state_code

    column state_name sync us_states.state_name

Denorm colocation of external values with derived values offers very high compression of logic definitions.

It's a "pay me now" trade. The write is more expensive in exchange for simpler modeling, simpler reads and writes, simpler stack.

The builder traps cycles, so we get termination. Builds are idempotent and additive, any-state to current. Ranged foreign keys are first class citizens (not just time series). Derived values are not subvertible. Race conditions and deadlocks eliminated (*except generating children can produce deadlocks the client must handle).

If you already have Postgres installed, you can get something usable in 10-20 minutes following the README.