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Re: Foreign key index on multiple columns
Posted by: Peter Brawley
Date: June 14, 2019 12:09PM

Easy to check ...
drop table if exists c,p;
create table p(pid int unsigned primary key);
create table c(
  cid int unsigned primary key,
  pid int unsigned,
  i int not null,
  foreign key(pid) references p(pid) on delete cascade on update cascade,
insert into p set pid=1;
insert into c set cid=1,pid=1,i=1;
update p set pid=2;
from p 
left join c using(pid);
| pid | cid  | pid  | i    |
|   2 |    1 |    2 |    1 |

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Re: Foreign key index on multiple columns
June 14, 2019 12:09PM

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