component.pin

What it is ¶

component.pin(ref_des, pin) yields one row per part-type pin of every placed component, where (ref_des, pin) names the pin and pin is its designator. It is the base pin-tier relation. Four others refine it: pin.role, pin.type, pin.net and pin.name. A row asserts only that the pin exists on a placed part, nothing about its role, direction, or connectivity.

For hardware engineers ¶

This relation enumerates every pin of a part, as the symbol’s pin list gives them. It has rows only when the source carries part-pin data (a KiCad symbol library, an EDIF cell), so a bare netlist with no symbols yields nothing. You query it to inventory pins, or as the left side of a join that asks a follow-up question about each one (what net is it on, what is its role). A multi-section part can share a pin, such as a power pin drawn in both halves of a dual op-amp. Such a pin appears once, deduplicated by designator.

For software engineers ¶

A pin is a member of a class instance. The analogy guide makes PartType the class, Component the instance, and the pin one declared field. component.pin lists those members for every instance. Rows are 1:1 with PinInst entities, and the pin-level rules quantify over those. It joins to pin.role / pin.type / pin.net / pin.name on (ref_des, pin), and each adds one attribute of the same member. An empty result means the design carries no part-pin data (a netlist-only source). The other tiers are silent in the same way when their data is missing.

Go projector ¶

pinFacts in stdlib/relations/facts.go iterates Model.Pins() and emits one component.pin(ref_des, pin) row per PinInst. The pin set is built once when the model loads. Each component’s sections are walked, and each declared pin designator is added once. A designator already seen in an earlier section is not re-added, so a multi-section part’s shared pins are counted once. One row per part-type pin; empty when no component declares pins.

Datalog ¶

Every pin the design declares:

component.pin(?r, ?p) => ?r

Join to pin.net to keep only the pins that actually connect to a net (the connected ones):

component.pin(?r, ?p), pin.net(?r, ?p, ?n) => ?n