[jira] [Created] (DERBY-6659) The Reference Guide should state how long a SET CONSTRAINTS command is good for

["Rick Hillegas (JIRA)" <ji...@apache.org>]

Rick Hillegas created DERBY-6659:
------------------------------------

             Summary: The Reference Guide should state how long a SET CONSTRAINTS command is good for
                 Key: DERBY-6659
                 URL: https://issues.apache.org/jira/browse/DERBY-6659
             Project: Derby
          Issue Type: Improvement
          Components: Documentation
    Affects Versions: 10.11.0.0
            Reporter: Rick Hillegas


A SET CONSTRAINTS command changes the state of a constraint only until the transaction ends (or another, overriding SET CONSTRAINTS command is issued). Once the transaction ends, the constraint reverts to the default behavior declared for it at CREATE/ALTER TABLE time. However, this behavior is not clear from the reference material on SET CONSTRAINTS: https://builds.apache.org/job/Derby-docs/lastSuccessfulBuild/artifact/trunk/out/ref/rrefsqljsetconstr.html

The following script shows this behavior:

{noformat}
connect 'jdbc:derby:memory:db;create=true' as conn1;

autocommit off;

call syscs_util.syscs_set_database_property( 'derby.locks.waitTimeout', '5' );
commit;

create table tprim
(
    keyCol  int primary key
);
create table tref
(
    refCol  int,
    constraint refcon foreign key( refCol ) references tprim( keyCol ) deferrable
);
insert into tprim( keyCol ) values ( 1 ), ( 2 ), ( 3 );
commit;

set constraints refcon deferred;

-- succeeds because we switched to deferred mode for this transaction
insert into tref( refCol ) values ( 4 );
rollback;

-- but fails the second time because the end of the previous transaction
-- reverted the refcon constraint to its default (immediate) mode
insert into tref( refCol ) values ( 4 );
{noformat}




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