[英]Postgres- hard delete with cascade to relation table
I am writing sql query (using postgres 14 ) to DELETE
row from tags
table:我正在编写 sql 查询(使用postgres 14 )以从tags
表中DELETE
行:
Tags table:标签表:
id ID | team_id team_id | name姓名 |
---|---|---|
1 1 | 91 91 | Dev Team开发团队 |
But, It should CASCADE
to the team_member_tag table too:但是,它也应该CASCADE
到team_member_tag表:
id ID | team_member_id team_member_id | tag_id tag_id |
---|---|---|
1 1 | 289 289 | 1 1 |
Joined by team_member table:由team_member表加入:
id ID | team_id team_id | member_id会员ID |
---|---|---|
289 289 | 91 91 | 1 1 |
I tested it, but It seems like my INNER JOIN
is out of order.我对其进行了测试,但似乎我的INNER JOIN
出现故障。 I do not know what I am doing wrong?我不知道我做错了什么?
My query:我的查询:
DELETE tag t, team_member_tag tmt
FROM tag
LEFT JOIN team_member_tag tmt ON t.id = tmt.team_member_id
LEFT JOIN team_member tm ON tm.id = tmt.team_member_id
WHERE team_member.member_id = :teamId
AND team_member.member_id = :teamMemberId
$stmt->bindValue("teamId", 91 PDO::PARAM_INT);
$stmt->bindValue("teamMemberId", 289, PDO::PARAM_INT);
I tried first with SELECT
, and it says query is OK but returns nothing:我首先尝试使用SELECT
,它说查询没问题,但什么也没返回:
SELECT
name
FROM tag as t
LEFT JOIN team_member_tag tmt ON t.id = tmt.team_member_id
LEFT JOIN team_member tm ON tm.id = tmt.team_member_id
WHERE name = 'Dev Team'
AND tmt.team_member_id = 289 AND tm.team_id = 91;
For postgres, you need a CTE to do that, if you don't have casacding references see对于 postgres,您需要一个 CTE 来执行此操作,如果您没有级联引用,请参阅
SELECT t.*, tmt.*
FROM tag t
INNER JOIN team_member_tag tmt ON t.id = tmt.tag_id
INNER JOIN team_member ON tmt.team_member_id = team_member.id
INNER JOIN member ON team_member.member_id = member.id
WHERE team_member.team_id = 91
AND team_member.member_id = 1;
id ID | team_id team_id | name姓名 | id ID | team_member_id team_member_id | tag_id tag_id |
---|---|---|---|---|---|
1 1 | 91 91 | Dev Team开发团队 | 1 1 | 289 289 | 1 1 |
SELECT 1
WITH Bdeletes AS (
DELETE FROM team_member_tag tmt
WHERE tmt.team_member_id IN (SELECT team_member.id
FROM team_member
WHERE team_member.team_id = 91
AND team_member.member_id = 1)
returning tmt.tag_id
)
DELETE from tag t
where t.id
IN( SELECT Tag_id FROM Bdeletes)
DELETE 1
SELECT * FROM tag
id ID | team_id team_id | name姓名 |
---|
SELECT 0
SELECT * FROM team_member_tag
id ID | team_member_id team_member_id | tag_id tag_id |
---|
SELECT 0
But if you add a REFERENCE you can do it in one adding more refences would also delete more rows from other tables但是,如果您添加一个 REFERENCE,您可以一次完成,添加更多引用也会从其他表中删除更多行
CREATE TABLE Tag
("id" int primary key, "team_id" int, "name" varchar(8))
;
INSERT INTO Tag
("id", "team_id", "name")
VALUES
(1, 91, 'Dev Team')
CREATE TABLE
INSERT 0 1
CREATE TABLE team_member_tag
("id" int, "team_member_id" int, "tag_id" int references Tag (id) on delete cascade )
;
INSERT INTO team_member_tag
("id", "team_member_id", "tag_id")
VALUES
(1, 289, 1)
;
CREATE TABLE
INSERT 0 1
CREATE TABLE team_member
("id" int, "team_id" int, "member_id" int)
;
INSERT INTO team_member
("id", "team_id", "member_id")
VALUES
(289, 91, 1)
;
CREATE TABLE
INSERT 0 1
CREATE TABLe member("id" int)
CREATE TABLE
INSERT INTO member VALUES(1)
INSERT 0 1
SELECT t.*, tmt.*
FROM tag t
INNER JOIN team_member_tag tmt ON t.id = tmt.tag_id
INNER JOIN team_member ON tmt.team_member_id = team_member.id
INNER JOIN member ON team_member.member_id = member.id
WHERE team_member.team_id = 91
AND team_member.member_id = 1;
id ID | team_id team_id | name姓名 | id ID | team_member_id team_member_id | tag_id tag_id |
---|---|---|---|---|---|
1 1 | 91 91 | Dev Team开发团队 | 1 1 | 289 289 | 1 1 |
SELECT 1
DELETE FROM tag
WHERE id IN
(SELECT tag_id FROM team_member_tag tmt
INNER JOIN team_member ON tmt.team_member_id = team_member.id
WHERE team_member.team_id = 91
AND team_member.member_id = 1)
DELETE 1
SELECT * FROM tag
id ID | team_id team_id | name姓名 |
---|
SELECT 0
SELECT * FROM team_member_tag
id ID | team_member_id team_member_id | tag_id tag_id |
---|
SELECT 0
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