[jira] [Created] (DERBY-6559) A immediate Fk constraint blows up iff its referenced PK is deferred and we delete a duplicate

["Dag H. Wanvik (JIRA)" <ji...@apache.org>]

Dag H. Wanvik created DERBY-6559:
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             Summary: A immediate Fk constraint blows up iff its referenced PK is deferred and we delete a duplicate
                 Key: DERBY-6559
                 URL: https://issues.apache.org/jira/browse/DERBY-6559
             Project: Derby
          Issue Type: Bug
          Components: SQL
            Reporter: Dag H. Wanvik
            Assignee: Dag H. Wanvik


Cf the following test case:

    /**
     * The referenced constraint (in the referenced table) is also a deferred
     * (unique/ok) constraint.
     * 
     * @throws SQLException 
     */
    public void testFKPlusUnique() throws SQLException {
        Statement s = createStatement(
                ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_UPDATABLE);
        
        try {
            s.executeUpdate(
                "create table ref_t(i int, " +
                "    constraint ct primary key(i) deferrable initially deferred)");
            s.executeUpdate(
                "create table t(i int unique not null, " +
                "    constraint c foreign key (i) references ref_t(i) " +
                "    deferrable initially immediate)");
            
            s.executeUpdate("insert into ref_t values 1,1");
            s.executeUpdate("insert into t values 1");
            
            // Now, the child (referencing table) is referencing one of the the
            // rows whose value is 1, so the reference is broken.
            
            // What happens when we delete the one copy before commit?
            ResultSet rs = s.executeQuery("select * from ref_t");
            rs.next();
            
            // Will this delete blow up? Hopefully not. Even though we have
            // default restrict action, there is another row that would
            // satisfy the constraint.
            rs.deleteRow();
            
            // Now there should be only one left, so the referenced table is
            // OK.
            commit();

Now, the constraint C throws when we do the "rs.deleteRow" above. But since there is (still) a row satisfying the FK, albeit a duplicate, I believe it should not.




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