Re: WIP: System Versioned Temporal Table - Mailing list pgsql-hackers

From Jean Baro
Subject Re: WIP: System Versioned Temporal Table
Date
Msg-id CA+fQeenbJDqNboYgFX34xhBA2Ygvz6T34raOU=EDti_W0Gb5KQ@mail.gmail.com
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In response to Re: WIP: System Versioned Temporal Table  (Vik Fearing <vik@postgresfriends.org>)
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Would these best practices be applicable by PostgreSQL to help avoid breaking changes for temporal tables?


Thanks

On Tue, Feb 15, 2022 at 5:08 PM Vik Fearing <vik@postgresfriends.org> wrote:
On 1/24/22 00:16, Corey Huinker wrote:
>> - Table schemas change, and all (SV active) AV items would logically
>> need to fit the active schema or be updated to do so. Different story
>> for SV, nothing there should ever need to be changed.
>>
> Yeah, there's a mess (which you state below) about what happens if you
> create a table and then rename a column, or drop a column and add a
> same-named column back of another type at a later date, etc. In theory,
> this means that the valid set of columns and their types changes according
> to the time range specified. I may not be remembering correctly, but Vik
> stated that the SQL spec seemed to imply that you had to track all those
> things.

The spec does not allow schema changes at all on a a system versioned
table, except to change the system versioning itself.
--
Vik Fearing




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