Re: Problem in AlterTableAddConstraint?

Can anyone comment on this?

>
> Browsing through backend/commands/command.c I noticed the following code:
>
> if (indexStruct->indisunique)
> {
> List *attrl;
>
> /* go through the fkconstraint->pk_attrs list */
> foreach(attrl, fkconstraint->pk_attrs)
> {
> Ident *attr=lfirst(attrl);
> found = false;
> for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0;
> i++)
> {
> int pkattno = indexStruct->indkey[i];
> if (pkattno>0)
> {
> char *name = NameStr(rel_attrs[pkattno-1]->attname);
> if (strcmp(name, attr->name)==0)
> {
> found = true;
> break;
> }
> }
> }
> if (!found)
> break;
> }
> }
>
> which is (I think) supposed to be checking for a unique index on the FK
> fields in the referenced table.
>
> Unfortunately, my reading of this code suggests it is doing the following:
>
> for each column in the FK
>
> see if we can find the column in the index
> if not, then die
>
> next FK column
>
> The problem with this is that it needs to ensure a 1:1 match between
> columns for the UNIQUE constraint requirement to be satisfied...I think.
>
> To give an example,
>
> create table c2(f1 integer, f2 integer, unique(f1,f2));
> create table c1(f1 integer, f2 integer, foreign key(f1) references
> c2(f1));
>
> is allowed with current sources.
>
> I'd guess that adding code to ensure the column lists are the same size
> would fix the problem.
>
>
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