2
所以我有一个表类似的结构:试图UPSERT一个表部分索引
CREATE TABLE x (
id SERIAL,
a character varying(1024) NOT NULL,
b character varying(2048),
c character varying(1024)
);
CREATE UNIQUE INDEX uniq_x_a ON x USING btree (a) WHERE (b IS NULL);
CREATE UNIQUE INDEX uniq_x_a_b ON x USING btree (a, b) WHERE (b IS NOT NULL);
现在我升级这种情况下,以9.5和要使用的ON CONFLICT DO UPDATE
。
所以执行这个
INSERT INTO x (a, b, c) VALUES ('hello', 'there', 'c1');
INSERT INTO x (a, b, c) VALUES ('hello', 'there', 'c2');
现在给我
ERROR: duplicate key value violates unique constraint "uniq_x_a_b"
DETAIL: Key (a, b)=(hello, there) already exists.
后来,当我做
INSERT INTO x (a, b, c) VALUES ('hello', 'there', 'c4')
ON CONFLICT ON CONSTRAINT uniq_x_a_b DO UPDATE SET c = excluded.c;
我得到
ERROR: constraint "uniq_x_a_b" for table "x" does not exist
我不明白,我违反了一个不存在的约束?任何人都有小费?
编辑
每我加
ALTER TABLE x ADD CONSTRAINT uniq_x_a_b_constraint UNIQUE (a, b);
所以这个现在适用于以下几种情况下建议:
INSERT INTO x (a, b, c) VALUES ('hello', 'there', 'c3')
ON CONFLICT ON CONSTRAINT uniq_x_a_b_constraint DO UPDATE SET c = excluded.c;
但失败了
INSERT INTO x (a, b, c) VALUES ('hello', NULL, 'c3')
ON CONFLICT ON CONSTRAINT uniq_x_a_b_constraint DO UPDATE SET c = excluded.c;
与
ERROR: duplicate key value violates unique constraint "uniq_x_a"
DETAIL: Key (a)=(hello) already exists.
我不能单独a
列添加一个唯一约束,因为它是被认为是唯一的a
和b
组合。似乎也不可能像创建索引一样在行的子集上构建约束。
a和b的组合应该是唯一的,只有b可以包含NULL值。 – Jan
@Jan,请参阅我的扩展答案。 –
是的,但是这在'INSERT INTO x(a,b,c)VALUES('hello',NULL,'c3')上失败ON CONFLICT ON CONSTRAINT uniq_x_a_b_constraint DO UPDATE SET c = excluded.c;' – Jan