Re: [Q] Load (or delete) order

Hi,
Yes, I understand what you are saying in your example, I did have a rule that there can be no circular dependencies in the database.
First, It should not be allowed to be created (but because oracle, and probably other db do not maintain the full dependency tree, they can not detect cycles).

But in the program, I did make an attempt to detect cycles -- that portion of the code did not really get tested though (because we do not have cycles in the dependencies).

Vladislav

Thomas Kyte <tkyte_at_us.oracle.com> wrote in message news:37b8f661.2012714_at_newshost.us.oracle.com...
> A copy of this was sent to "Vladik" <reason_at_shadow.net>
> (if that email address didn't require changing)
> On Fri, 13 Aug 1999 21:14:51 -0400, you wrote:
>
> >Well,
> >I did not hear any responses sofar. So I guess
> >there is no script like that. I was also
> >told that Oracle does not provide any program that helps in
> >that area. I am surprised, it seems like figuring
> >out dependencies amongst tables is something a lot
> >of people would be interested it.
> >
>
> there are the views all_dependencies and user_dependencies that show the
> relationships. In the end tho -- its not a 100% solvable problem.
>
> put these tables into your database and see what happens to your C program
:)
> you might be surprised..
>
> SQL> create table t1 ( x int primary key, y int );
>
> Table created.
>
> SQL> create table t2 ( a int primary key, b int references t1(x) );
>
> Table created.
>
> SQL> alter table t1 add constraint t1_fk foreign key (y) references t2(a);
>
> Table altered.
>
> SQL> create table t3 ( x int primary key, y int references t3(x) );
>
> Table created.
>
>
>
> >Anyways, I solved this by writing a C program
> >that builds a dependency tree structure. And
> >then prints out notes on each level.
> >Each node is either a parent or a child. A parent
> >node represents a table that needs to be populated
> >before a child table can be populated. Parent-Child
> >relation ship can be obtained from user_constraints.
> >Once the tree is built if traversed from top level
> >to bottom -- table names for the load order will
> >be printed, and the delete order is just a reverse of load.
> >
> >Vladislav
> >
> >
> ><vladik854_at_my-deja.com> wrote in message
news:7ond1k$vtc$1_at_nnrp1.deja.com...
> >> Hello,
> >> does anyone know of a script that can figure
> >> out the load (or delete) order for oracle tables
> >> We have a lot of tables with tons of referential integrity
> >> constraints and I need to know the order at wich I have
> >> to delete tables (it is a reverse of load order)
> >>
> >> I know that there is a way to do that because Oracle importer
> >> does the same things when loading tables .
> >>
>
> No, it loads the tables and then goes back and enables constraints. It
does not
> bother with trying to figure out (the sometimes impossible) load order of
> tables....
>
>
> >> Thanks in advance.
> >> If, possible, I would appreciate an e-mail
> >> back at vlpa_at_daleen.com
> >>
> >>
> >> Sent via Deja.com http://www.deja.com/
> >> Share what you know. Learn what you don't.
> >
>
>
> --
> See http://govt.us.oracle.com/~tkyte/ for my columns 'Digging-in to
Oracle8i'...
> Current article is "Part I of V, Autonomous Transactions" updated June
21'st
>
> Thomas Kyte tkyte_at_us.oracle.com
> Oracle Service Industries Reston, VA USA
>
> Opinions are mine and do not necessarily reflect those of Oracle
Corporation Received on Wed Aug 18 1999 - 18:36:57 CDT