ALTER TABLE relation_types ADD COLUMN updated_at TIMESTAMPTZ NOT NULL DEFAULT now();

CREATE TABLE phrase_bindings (

id UUID PRIMARY KEY,

kb_id UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,

-- 归一过的短语：空白折成一个空格、小写、去两端空白（同 type_bindings.kind_word）

phrase TEXT NOT NULL,

-- 两端的类；空表示那一端的类别词还没绑到类（或宾语是字面值）。类删了绑定跟着走

subject_type_id UUID REFERENCES entity_types(id) ON DELETE CASCADE,

object_type_id UUID REFERENCES entity_types(id) ON DELETE CASCADE,

-- 宾语是字面值（金额、百分比、称号）而不是一样东西

object_is_value BOOLEAN NOT NULL DEFAULT false,

-- status 为 none / undecided 时为空；属性删了绑定跟着走

relation_type_id UUID REFERENCES relation_types(id) ON DELETE CASCADE,

-- forward：陈述的主语是属性的主语；reverse：陈述的宾语是

direction TEXT CHECK (direction IN ('forward', 'reverse')),

-- bound 绑上了

-- none 没有属性对得上：陈述留在开放图谱，签名计入工作台的建议

-- undecided 两票不一致，留给审核（#725 对齐队列）

status TEXT NOT NULL CHECK (status IN ('bound', 'none', 'undecided')),

-- 得出这个判定的那几票

votes JSONB,

-- 判定时这个签名下有几条陈述，三条例句——工作台按它排建议

statement_count INTEGER NOT NULL DEFAULT 0,

examples TEXT[] NOT NULL DEFAULT '{}',

decided_at TIMESTAMPTZ NOT NULL DEFAULT now(),

-- 人的判定不被代理覆盖

decided_by TEXT NOT NULL DEFAULT 'agent' CHECK (decided_by IN ('agent', 'person')),

-- 一个库里一条签名一行；类为空也是一种签名（NULLS NOT DISTINCT）

UNIQUE NULLS NOT DISTINCT (kb_id, phrase, subject_type_id, object_type_id, object_is_value),

-- 绑上了就得有属性和方向，没绑就都不能有

CONSTRAINT phrase_bindings_shape

CHECK ((status = 'bound') = (relation_type_id IS NOT NULL)

AND (status = 'bound') = (direction IS NOT NULL)),

-- 宾语是字面值的签名没有宾语类

CONSTRAINT phrase_bindings_value_has_no_class

CHECK (NOT object_is_value OR object_type_id IS NULL)

);

CREATE INDEX phrase_bindings_kb_status_idx ON phrase_bindings (kb_id, status);