Re: Storing original rows before update or delete

If I restrict any DML operation to internal tables (history tables) in
phase of parse analyze, nobody can do such operation regardless of user
rights. However, triggers can't be used in this case.

2011/11/4 Szymon Guz <mabewlun(at)gmail(dot)com>

>
>
> On 4 November 2011 10:20, Miroslav Šimulčík <simulcik(dot)miro(at)gmail(dot)com>wrote:
>
>> Hi.
>>
>> I'm working on transactiontime temporal support for postgresql 9.0.4.
>> Each original table with transactiontime support has associated history
>> table, where original row is stored before each update or delete operation
>> on it. Both original and history tables have internal timestamp columns for
>> storing the period of validity of row versions. History tables are internal
>> and I want to restrict any DML operation on it, so nobody can change
>> history of operations made on original table. Problem is, that I don't know
>> where to implement the mechanism for storing original rows to history
>> tables. Rewrite rules are not suitable, because they are not working with
>> inheritance and I can't use triggers, because inserts to history tables are
>> restricted. Can you point me to place in postgresql backend where can i
>> implement this and maybe give me some hints about how to do it correctly?
>>
>> Thank you.
>>
>> Best regards
>> Miroslav Simulcik
>>
>
>
> Hi,
> use triggers with security definer so the owner of the triggers and the
> history table can insert into it, but normal user cannot - this user only
> is able to change data in original table, and triggers will copy the data,
> but will be executed using the first user credentials.
> http://www.postgresql.org/docs/9.0/interactive/sql-createfunction.html
>
> On the other hand: superuser always can delete data from a table, so you
> cannot stop him from doing that.
>
> regards
> Szymon
>
>