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create table t1 (f1 int primary key) engine=innodb;
create table t2 (f1 int primary key,
constraint c1 foreign key (f1) references t1(f1)
on update cascade
on delete cascade) engine=innodb;
create table t3 (f1 int primary key,
constraint c2 foreign key (f1) references t1(f1)
on update cascade
on delete cascade) engine=innodb;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) NOT NULL,
PRIMARY KEY (`f1`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) NOT NULL,
PRIMARY KEY (`f1`),
CONSTRAINT `c1` FOREIGN KEY (`f1`) REFERENCES `t1` (`f1`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
show create table t3;
Table Create Table
t3 CREATE TABLE `t3` (
`f1` int(11) NOT NULL,
PRIMARY KEY (`f1`),
CONSTRAINT `c2` FOREIGN KEY (`f1`) REFERENCES `t1` (`f1`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
insert into t1 values (1);
insert into t1 values (2);
insert into t1 values (3);
insert into t2 values (1);
insert into t2 values (2);
insert into t2 values (3);
insert into t3 values (1);
insert into t3 values (2);
insert into t3 values (3);
select f1 from t1;
f1
1
2
3
select f1 from t2;
f1
1
2
3
select f1 from t3;
f1
1
2
3
set @save_dbug = @@debug_dbug;
set debug_dbug = '+d,dml_cascade_only_once';
set debug_dbug = '+d,row_upd_cascade_lock_wait_err';
update t1 set f1 = 100 where f1 = 2;
select f1 from t1;
f1
1
3
100
select f1 from t2;
f1
1
3
100
select f1 from t3;
f1
1
3
100
set debug_dbug = @save_dbug;
drop table t2;
drop table t3;
drop table t1;
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