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删除SQLITE ANDROID上的级联_Android_Sqlite_Cascading Deletes - Fatal编程技术网

删除SQLITE ANDROID上的级联

删除SQLITE ANDROID上的级联,android,sqlite,cascading-deletes,Android,Sqlite,Cascading Deletes,我有3个表,比如A、B、C。表A有主键列a1,它是表B的外键。表B有主键b1,它是表C的外键。表C有主键c1。我正在通过级联删除从表a中删除一行。its从表B中删除相应的值,但不在表C中。任何人都可以用示例来解释。两个外键约束必须标记为ON DELETE CASCADE: > CREATE TABLE A(a1 PRIMARY KEY); > CREATE TABLE B(b1 PRIMARY KEY, fa REFERENCES A(a1) ON DELETE CASCADE);

我有3个表,比如A、B、C。表A有主键列a1,它是表B的外键。表B有主键b1,它是表C的外键。表C有主键c1。我正在通过级联删除从表a中删除一行。its从表B中删除相应的值,但不在表C中。任何人都可以用示例来解释。

两个外键约束必须标记为ON DELETE CASCADE:

> CREATE TABLE A(a1 PRIMARY KEY);
> CREATE TABLE B(b1 PRIMARY KEY, fa REFERENCES A(a1) ON DELETE CASCADE);
> CREATE TABLE C(c1 PRIMARY KEY, fb REFERENCES B(b1) ON DELETE CASCADE);
> INSERT INTO A VALUES (1);
> INSERT INTO B VALUES (2, 1);
> INSERT INTO C VALUES (3, 2);
> DELETE FROM A;
> SELECT COUNT(*) FROM C;
0

. 检查这个,如果它有帮助的话,谢谢,但是我可以用这个链接中给出的2个表来做,但是问题是我需要用3个表来做