> > > Yes, that's the whole point. If I have a constraint on a table, I think > > > it should *never* be possible for that constraint to be violated. If a > > > subtable should not have constraint the supertable has, it shouldn't > > > inherit from the supertable. > > > > If you want that, you simply need to only create constraints that apply to > > all tables in the hierarchy. Note that you *can* do this. It should imho be > > the default behavior. > > So what you're saying is that constraints shouldn't be inherited?
No. I even said that inheriting should be the default. > > > To do otherwise breaks the relational model. > > > > That is probably a point of argument. Imho the inheritance feature > > is something orthogonal to the relational model. It is something else, and > > thus cannot break the relational model. > > So then constraints must be inherited. The relational model, if I > am not incorrect here, says that, given a table definition such as > this: > > CREATE TABLE my_table ( > my_key int PRIMARY KEY, > my_value text UNIQUE, > my_other_value int CHECK (my_other_value > 0) > ) A local constraint should be made obvious from looking at the schema, a possible syntax (probably both ugly :-): CHECK my_table ONLY (my_other_value > 0) or CHECK LOCAL (my_other_value > 0) > > You will never, ever, when selecting from this table, have > returned to you > > 1. two rows with the same value of my_key but different values > for the other columns, > > 2. two rows with the same value of my_value but different values > for the other columns, or > > 3. a row in which the value of my_other_value is not > greater than zero. > Well, that is where I do not think this is flexible enough, and keep in mind that all triggers and rules would then also need such restrictions. > I would strongly object to that. Regardless whether your objection is *strong* or not :-) If you don't like the feature (to add a local constraint), don't use it. (Remember you are talking about removing an implemented feature) Andreas ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
