Re: How to determine the Oracle session's constraint state?

"John Peterson" <j0hnp_at_comcast.net> wrote in message news:vOOdnaKmLoUeGOzWnZ2dnUVZ_tGdnZ2d_at_giganews.com...
>
> "Mark D Powell" <Mark.Powell2_at_hp.com> wrote in message
> news:1e6c1dd0-add9-41c3-a505-a0800c61c9f8_at_c4g2000yqa.googlegroups.com...
>> On Feb 8, 1:09 pm, "John Peterson" <j0..._at_comcast.net> wrote:
>>> "Mark D Powell" <Mark.Powe..._at_hp.com> wrote in
>>> messagenews:63f31d18-8229-43b2-9fbb-1c79cb5bdefc_at_l26g2000yqd.googlegroups.com...
>>>
>>>
>>>
>>>
>>>
>>> > On Feb 8, 12:08 pm, "John Peterson" <j0..._at_comcast.net> wrote:
>>> >> Hello!
>>>
>>> >> First time poster in this forum -- please forgive me if this is the
>>> >> wrong
>>> >> place for my question. I've exhausted a web search on this issue,
>>> >> and
>>> >> was
>>> >> hoping that this might be a more targeted approach.
>>>
>>> >> I am trying to programmatically determine the current session's
>>> >> constraint
>>> >> state (immediate, deferred, or default).
>>>
>>> >> I have a procedure that I'd like to implement which would essentially
>>> >> temporarily set the constraints "deferred" (e.g. SET CONSTRAINTS ALL
>>> >> DEFERRED), perform some work, and then restore the constraint setting
>>> >> to
>>> >> the
>>> >> original state (e.g., immediate). However, I'm having a difficult
>>> >> time
>>> >> identifying how to determine the current state of the constraints.
>>>
>>> >> Any help would be very much appreciated!
>>>
>>> >> Kind regards,
>>>
>>> >> John Peterson
>>>
>>> > See the DEFERRABLE and DEFERRED columns in the ALL_, USER_, or
>>> > DBA_CONSTRAINTS views (documented in the Oracle version# Reference
>>> > manual).
>>>
>>> > By the way making a PK or UK deferrable would require use of a non-
>>> > unique index to support the constraint instead of the standard unique
>>> > index.
>>>
>>> > HTH -- Mark D Powell --
>>>
>>> Thanks, Mark!
>>>
>>> Unfortunately, those metadata views don't seem to reflect the current
>>> session state.
>>>
>>> That is, if I have some FKs that are deferrable (but initially
>>> immediate)
>>> (e.g., CONSTRAINT_TYPE = 'R'), it will show DEFERRABLE/IMMEDIATE in the
>>> DEFERRABLE/DEFERRED columns.
>>>
>>> But, after I run:
>>>
>>> SET CONSTRAINTS ALL DEFERRED
>>>
>>> Those columns are still DEFERRABLE/IMMEDIATE in the metadata views.
>>>
>>> I had thought maybe I could obtain this information from the SYS_CONTEXT
>>> function to get the current session state information, but none of the
>>> options seem applicable.
>>>
>>> Any other ideas?- Hide quoted text -
>>>
>>> - Show quoted text -
>>
>> I understand the question now. When you follow the directions in the
>> manual to set contrainst processing deferred in your session as per
>> http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/general.htm#sthref1939
>> how do you check to see the current status of constraint processing.
>> Note that the command is valid only for a single transaction so it
>> automatically resets on commit or rollback.
>>
>> I do not know how to check while you have an active transaction in
>> progress, but I can remember dealing with a similar question where you
>> set a session parameter and where to see it since it is not a database
>> parameter and does not show in v$parameter. I will look and see if I
>> can find a note on whatever parameter I reseached before, if it had an
>> answer, and if that answer applies.
>>
>> HTH -- Mark D Powell --
>>
>
> Thanks Mark!
>
> One thing that I found from the AskTom site (but haven't verified) that
> there's a subtle distinction between:
>
> SET CONSTRAINTS ALL DEFERRED;
>
> and
>
> ALTER SESSION SET CONSTRAINTS=DEFERRED;
>
> Apparently the first will operate at the transaction scope, and the second
> at the session scope. I had always thought the two were interchangeable.
>
> But, yes -- you understand my question now: how can we programmatically
> determine the current "state" of this setting?
>
> Thanks again!

Upon further review, I see that both settings *are* the same -- they affect the transaction scope (the session-based one just acts as if you submitted the statement before every transaction).

But figuring out how to ascertain the current state of this setting is proving to be challenging!   Received on Tue Feb 09 2010 - 10:26:10 CST