SQL 在 sqlite3 中删除级联
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ON DELETE CASCADE in sqlite3
提问by LuckyLuke
I have the following structure: (Sorry for awkward names, it is because it is a sqlite database for my iPhone app which is not released yet)
我有以下结构：（对不起，名字笨拙，这是因为它是我的 iPhone 应用程序的 sqlite 数据库，尚未发布）
CREATE TABLE klb_log (
id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
log_comment varchar(512)
)
CREATE TABLE klb_log_food_maps (
uid integer,
did integer,
PRIMARY KEY (uid,did),
FOREIGN KEY (uid) references klb_log(id) ON DELETE CASCADE,
FOREIGN KEY (did) references klb_food(id) ON DELETE CASCADE
)
CREATE TABLE klb_food (
id integer,
description varchar(255),
PRIMARY KEY (id)
)
Is there a reason why the row in klb_log_food_mapsis not removed when I delete a row in klb_log?
klb_log_food_maps当我删除in 中的一行时，是否有理由不删除该行klb_log？
回答by Paul Lefebvre
Foreign key support is not enabled in SQLite by default. You need to enable it manually each time you connect to the database using the pragma:
默认情况下，SQLite 中未启用外键支持。每次使用编译指示连接到数据库时，您都需要手动启用它：
PRAGMA foreign_keys = ON
回答by GKK
Do you have foreign key support enabled?
您是否启用了外键支持？
query PRAGMA foreign_keys = ON;to turn it on
查询PRAGMA foreign_keys = ON;以将其打开
