1.  - Your Rust module can define a column type XX, which you can add through the table definition.
    - When a row is saved, the framework calls the registered modules’ row hooks.
    - You implement your module’s hook and choose whether its logic runs for every table, only tables containing XX, or
      another condition.

    - If you want it to affect only the XX column, your hook selects and processes that column’s value from the supplied
      row.

    - The framework doesn’t automatically make those choices. You implement the filtering and column-specific behavior;
      modules without a row-hook implementation default to doing nothing.

2.