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https://issues.apache.org/jira/browse/DERBY-6527?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13991251#comment-13991251
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Dag H. Wanvik edited comment on DERBY-6527 at 5/6/14 10:30 PM:
---------------------------------------------------------------
Running the script below:
{code}
connect 'jdbc:derby:memory:wombat;create=true';
autocommit off;
create table t(i int primary key);
create table t2(i int unique, constraint c1 foreign key(i) references t(i) on
delete set null);
create table t3(i int, constraint c2 foreign key(i) references t2(i) on update
no action /* or RESTRICT */ );
insert into t values 1;
insert into t2 values 1;
insert into t3 values 1;
delete from t;
{code}
gave this error on the delete:
{code}
ERROR 23503: UPDATE on table 'T2' caused a violation of foreign key constraint
'C2' for key (1). The statement has been rolled back.
{code}
so, it seems this can't happen:
{quote}
(Again, if the dependent table also has dependent tables,
nullable columns in those tables' foreign keys are also set to null.)
{quote}
If we allowed ON UPDATE SET NULL, it would make sense.
was (Author: dagw):
Running the script below:
{code}
connect 'jdbc:derby:memory:wombat;create=true';
autocommit off;
create table t(i int primary key);
create table t2(i int unique, constraint c1 foreign key(i) references t(i) on
delete set null);
create table t3(i int, constraint c2 foreign key(i) references t2(i) on update
no action /* or RESTRICT */ );
insert into t values 1;
insert into t2 values 1;
insert into t3 values 1;
delete from t;
{code}
gave this error on the delete:
{code}
ERROR 23503: UPDATE on table 'T2' caused a violation of foreign key constraint
'C2' for key (1). The statement has been rolled back.
{code}
so, it seems this can't happen:
{quote}
(Again, if the dependent table also has dependent tables,
nullable columns in those tables' foreign keys are also set to null.)
{quote}
If we allowed UP UPDATE SET NULL, it would make sense.
> Fix errors in foreign keys documentation
> ----------------------------------------
>
> Key: DERBY-6527
> URL: https://issues.apache.org/jira/browse/DERBY-6527
> Project: Derby
> Issue Type: Bug
> Components: Documentation
> Affects Versions: 10.10.1.1
> Reporter: Dag H. Wanvik
> Assignee: Kim Haase
>
> Cf this email thread:
> http://apache-database.10148.n7.nabble.com/Foreign-key-semantics-as-documented-td138227.html
> Our documentation in the reference manual on foreign keys/referential actions
> has errors.
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