ALTER TABLE relation_types

-- `p⁻¹ = q`。**单向存，双向用。**

--

-- 不加触发器去自动回填 `q.inverse_of = p`：那会把一条语义规则藏进数据库，

-- 而绕过它的路不止一条（RDF 导入、直接 SQL）。改在读取公理时归一化——

-- 载入那一处认这件事，绕不过去，也测得动（`reasoning::axioms_of`）。

ADD COLUMN inverse_of UUID REFERENCES relation_types(id) ON DELETE SET NULL,

-- `p ⊑ q`：断言了具体的，通用的也成立（`ceo_of ⊑ works_at`）。

-- 链要防成环，R0 那边加检查——与 `entity_types` 的父类环是同一类问题

ADD COLUMN sub_property_of UUID REFERENCES relation_types(id) ON DELETE SET NULL;

ALTER TABLE relation_types

ADD CONSTRAINT relation_types_sub_property_not_self

CHECK (sub_property_of IS NULL OR sub_property_of <> id);

CREATE INDEX relation_types_inverse_idx ON relation_types (inverse_of)

WHERE inverse_of IS NOT NULL;

CREATE INDEX relation_types_sub_property_idx ON relation_types (sub_property_of)

WHERE sub_property_of IS NOT NULL;

ALTER TABLE rules DROP CONSTRAINT IF EXISTS rules_kind_check;

ALTER TABLE rules ADD CONSTRAINT rules_kind_check

CHECK (kind IN ('transitive', 'symmetric', 'inverse', 'sub_property'));

ALTER TABLE ontology_defects DROP CONSTRAINT IF EXISTS ontology_defects_kind_check;

ALTER TABLE ontology_defects ADD CONSTRAINT ontology_defects_kind_check

CHECK (kind IN (

'symmetric_and_asymmetric', 'transitive_and_functional',

'subclass_cycle', 'disjoint_with_ancestor', 'inherits_disjoint',

'inverse_of_itself', 'inverse_not_mutual', 'sub_property_cycle'

));