[英]LEFT JOIN to leftJoin() in Doctrine 1 - how to do it properly?
[英]How to properly match the left join?
我正在嘗試正確匹配左聯接,在該聯接中您將刪除該X過濾器中記錄的filter
和信息。
表d_category
filter_id
7
8
表d_name
id | filter_id
10 | 7
11 | 7
12 | 7
表product_d
product_id | d_name_id
50 | 10
50 | 11
50 | 12
查詢
$this->db->query("DELETE FROM product_d
LEFT JOIN d_name ON (product_d.d_name_id = d_name.id)
WHERE"); // what should this clause be?
我假設您正在尋找級聯刪除 。 如果是這樣的話:
如果將外鍵配置為具有cascade delete
,則從父表中刪除記錄時,所有相關數據也將被刪除。
CREATE TABLE rooms (
room_no INT PRIMARY KEY AUTO_INCREMENT,
room_name VARCHAR(255) NOT NULL,
building_no INT NOT NULL,
FOREIGN KEY (building_no)
REFERENCES buildings (building_no)
ON DELETE CASCADE
);
那么當您刪除建築物時,房間也會被刪除
DELETE FROM buildings
WHERE
building_no = 2;
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