drop table if exists t1,t2;
create table t1 (
a int not null references t2,
b int not null references t2 (c),
primary key (a,b),
foreign key (a) references t3 match full,
foreign key (a) references t3 match partial,
foreign key (a,b) references t3 (c,d) on delete no action
on update no action,
foreign key (a,b) references t3 (c,d) on update cascade,
foreign key (a,b) references t3 (c,d) on delete set default,
foreign key (a,b) references t3 (c,d) on update set null);
create index a on t1 (a);
create unique index b on t1 (a,b);
drop table t1;
create table t1 (id int primary key) engine = innodb;
create table t2 (id int PRIMARY KEY, FOREIGN KEY (id) REFERENCES t1(id)) engine=innodb;
insert into t1 values (1), (2), (3), (4), (5), (6);
insert into t2 values (3), (5);
delete from t1;
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`id`) REFERENCES `t1` (`id`))
select * from t1;
id
1
2
3
4
5
6
delete ignore from t1;
Warnings:
Error	1451	Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`id`) REFERENCES `t1` (`id`))
Error	1451	Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `t2_ibfk_1` FOREIGN KEY (`id`) REFERENCES `t1` (`id`))
select row_count();
row_count()
-1
select * from t1;
id
3
5
drop table t2;
drop table t1;