Re: Detecting which columns a query will modify in a function called by a trigger

po 2. 3. 2020 v 19:59 odesílatel stan <stanb(at)panix(dot)com> napsal:

> I need to implement a fairly fine grained security model. Probably a bit
> finer that I can do with the standard ownership functionality.
>
> My thinking on this is to create a table that contains the users, and a
> "permission bit" for each function that they may want to do, vis a vi
> altering an existing row,or rows, or inserting new rows.
>
> Looks relatively straight forward, if fairly time consuming to do. But I
> would need to know which column(s) a given query would add..alter from the
> function to implement this via a trigger. looks like I see most of what I
> need t do this in the docs, but I can't quite figure out if I can get this
> down to what column(s) a given trigger will modify. Is this possible?
>

You can compare NEW and OLD record. It is pretty hard in PLpgSQL, but easy
with hstore or jsonb, or with PLPerl or PLPythonu

Regards

Pavel

>
>
> --
> "They that would give up essential liberty for temporary safety deserve
> neither liberty nor safety."
> -- Benjamin Franklin
>
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>