Re: Side effect of replacing a table with a view
- From: Arul Ramachandran <contactarul@xxxxxxxxx>
- To: vlado@xxxxxxxxxx
- Date: Sat, 23 Apr 2005 18:56:54 -0700
May be a 3rd alternative?
Is there a public synonym 'a' on table 'a'?
Assuming the application does not use the schema-name to connect to the
database and it uses an user_id to connect to the database AND assuming the
application code does not have schema-name.'a' but just 'a', then you can
consider dropping the public synonym and creating a view for the user:
drop public synonym a;
connect as schema
grant select on a to <user_id>;
connect as user_id
create view <user_id>.a as select <existing columns> from <schema_name>.a
If this works fine, only then add columns to the table 'a'. Easier to
backout too...
Cheers!
Arul
On 4/22/05, Vlado Barun <vlado@xxxxxxxxxx> wrote:
>
> I'm looking for input on what possible negative side effects I could
> encounter, if I replace a table with a view.
>
> Situation:
>
> I need to add a few columns to an existing, non-partitioned, heap table
> (let's call it "a"). However, I have identified a large number of "select
> *
> " queries against this table. Finding where these queries are coming from
> and changing them is not feasible within the current environment.
>
> So, I'm basically looking at two alternatives:
>
> 1. rename the existing table to "b", add the new columns to it and
> create a view named "a". The view will not expose any of the new columns
> 2. create another table "a_ext", with the same PK as "a", enforce RI
> (cascade delete), add the new columns to it. Also add an update trigger on
> "a", in case the PK in "a" gets updated, so that the PK in "a_ext" gets
> updated too.
>
> I prefer #1, but I'm concerned about possible negative side effect of
> renaming the table. Let's not worry about downtime, since it's not an
> issue
> in this environment. However, since table "a" is a very critical table, we
> need to make sure we do not break any existing code.
>
> We use Oracle 8.1.7.0 <http://8.1.7.0>, and yes it is .0, not .4
>
> Question:
>
> Are there any operations that could fail as the result of replacing the
> table with a view?
>
> Vlado Barun, M.Sc.
>
> Senior Data Architect, Cadre5
>
> www.cadre5.com <http://www.cadre5.com> <http://www.cadre5.com/>
>
> --
> //www.freelists.org/webpage/oracle-l
>
--
Arul
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