Re: Re: Changing the default value of an inherited column

ncm@zembu.com (Nathan Myers) writes:
> On Sat, Mar 31, 2001 at 07:44:30PM -0500, Tom Lane wrote:
>> That is:
>> 
>> create table p1 (f1 int default 1);
>> create table p2 (f1 int default 2);
>> create table c1 (f2 float) inherits(p1, p2);   # XXX
>> 
>> would draw an error about conflicting defaults for c1.f1, but
>> 
>> create table c1 (f1 int default 3, f2 float) inherits(p1, p2);
>> 
>> would be accepted (and 3 would become the default for c1.f1).
>> 
>> This would take a few more lines of code, but I'm willing to do it if
>> people think it's a safer behavior than picking one of the inherited
>> default values.

> Allowing the line marked XXX above, but asserting no default for 
> c1.f1 in that case, would be equally safe.  (A warning would be 
> polite, anyhow.)

The trouble with that is that we don't have such a concept as "no
default", if by that you mean "INSERTs *must* specify a value".
What would really happen would be that the effective default would
be NULL, which I think would be fairly surprising behavior, since
none of the three tables involved asked for that.

I have committed code that raises an error in cases such as XXX above.
Let's try it like that for awhile and see if anyone complains ...
        regards, tom lane