>
> On Mon, Oct 25, 2010 at 15:11, Peter Eisentraut wrote:
>
>> Example #4: PK is period, FK is timestamp. FK must be contained in some
>> PK period.
>>
>> CREATE TABLE pk (a period PRIMARY KEY, ...);
>>
>> CREATE TABLE fk (x timestamp REFERENCES pk (a), ...);
>>
>> As above, we can probably arra
On Mon, Oct 25, 2010 at 15:11, Peter Eisentraut wrote:
> Example #4: PK is period, FK is timestamp. FK must be contained in some
> PK period.
>
> CREATE TABLE pk (a period PRIMARY KEY, ...);
>
> CREATE TABLE fk (x timestamp REFERENCES pk (a), ...);
>
> As above, we can probably arrange the opera
On 10/26/10 11:53 AM, Jeff Davis wrote:
> Intuitively, I would expect all 1's to be replaced by 6's in all arrays.
> But I can now see why you would be hesitant to try to support that.
If people want cascading update to work, they shouldn't be denormalizing.
--
On tis, 2010-10-26 at 11:53 -0700, Jeff Davis wrote:
> Case #2 is the strange one, I think. It's not actually just an
> adaptation of #1. #1 requires that all elements of the array have a
> corresponding PK value; but #2 just requires that one of them does.
> Peter, can you clarify case #2? Did you
On Mon, 2010-10-25 at 17:57 -0700, Greg Stark wrote:
> On Mon, Oct 25, 2010 at 5:24 PM, Jeff Davis wrote:
> > I think that's easier when the PK must contain the FK, because then you
> > only need to lock one record. Even when you need to lock multiple
> > records, it seems feasible, and is just an
On Tue, 2010-10-26 at 20:25 +0300, Peter Eisentraut wrote:
> Let's say you have
>
> PK
>
> 1
> 2
> 3
> 4
> 5
>
> FK
>
> [1,2,3]
> [3,4,5]
> [4,4,4]
>
> When you delete PK = 3, what do you expect to happen? OK, you might
> decide to delete the first two rows from the FK table. This might or
On mån, 2010-10-25 at 17:57 -0700, Greg Stark wrote:
> Well if you lock multiple records then it's not clear what operations
> you should conflict with. Removing any one of them wouldn't actually
> invalidate the foreign key reference unless you remove the last one.
>
> I always assumed this was w
On mån, 2010-10-25 at 17:38 -0700, Jeff Davis wrote:
> > Implementing the foreign key side of this merely requires the system
> to
> > have some knowledge of the required "contains" operator, which it
> does
> > in the array case, and something can surely be arranged for the
> range
> > case. The
On mån, 2010-10-25 at 22:10 +0200, Pavel Stehule wrote:
> 2010/10/25 Robert Haas :
> >> Example #1: Foreign key side is an array, every member must match some
> >> PK.
> >>
> >> CREATE TABLE pk (a int PRIMARKY KEY, ...);
> >>
> >> CREATE TABLE fk (x int[] REFERENCES pk (a), ...);
>
> What about op
On Mon, Oct 25, 2010 at 5:24 PM, Jeff Davis wrote:
> I think that's easier when the PK must contain the FK, because then you
> only need to lock one record. Even when you need to lock multiple
> records, it seems feasible, and is just an index lookup, right? Do you
> see a particular problem?
Wel
On Mon, 2010-10-25 at 22:11 +0300, Peter Eisentraut wrote:
> Currently, foreign keys only work with the = operator (the name might be
> different, but it needs to behave like equality). I'm thinking there
> are other scenarios that could be useful, for example with arrays and
> range types.
I agr
On Mon, 2010-10-25 at 12:34 -0700, Greg Stark wrote:
> On Mon, Oct 25, 2010 at 12:11 PM, Peter Eisentraut wrote:
> > Is this sort of thing feasible? Has anyone done more research into the
> > necessary details?
>
> I think the problems arise when you try to figure out what records you
> need to
2010/10/25 Robert Haas :
> On Mon, Oct 25, 2010 at 3:11 PM, Peter Eisentraut wrote:
>> Currently, foreign keys only work with the = operator (the name might be
>> different, but it needs to behave like equality). I'm thinking there
>> are other scenarios that could be useful, for example with arr
On Mon, Oct 25, 2010 at 3:11 PM, Peter Eisentraut wrote:
> Currently, foreign keys only work with the = operator (the name might be
> different, but it needs to behave like equality). I'm thinking there
> are other scenarios that could be useful, for example with arrays and
> range types.
>
> Exa
On Mon, Oct 25, 2010 at 12:11 PM, Peter Eisentraut wrote:
> Is this sort of thing feasible? Has anyone done more research into the
> necessary details?
I think the problems arise when you try to figure out what records you
need to lock to prevent someone from deleting the referenced rows
before
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