Re: Referential Integrity Enforcement: Do With Constraints or Triggers?

Oops. This is the post I meant to link to:

http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&oe=UTF-8&frame=right&th=83c9a6fa06bd88fb&seekm=a20d28ee.0207260158.3ecabf94%40posting.google.com#link13

internetmaster wrote:
> In an earlier thread I mentioned the following observation:
>
> http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&oe=UTF-8&threadm=a20d28ee.0207260158.3ecabf94%40posting.google.com&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26group%3Dcomp.databases.oracle.tools
>
>
>
> I was wrong about one thing. The database does have primary keys
> defined, but no foreign keys. I went browsing through the data
> dictionary and found that the database has a ton of Triggers. It appears
> they're using Triggers to enforce the referential integrity rather than
> using constraints.
>
> They have Insert triggers on the parent tables that handle cascade
> deletes and prevent illegal inserts on child tables where they key value
> on the parent table doesn't exist.
>
> My question is it less expensive to handle the RI this way? I can see
> where creating a ton of constraints would get to be cumbersome and
> perhaps Triggers would be easier from a maintenance perspective.
>
> For example, there is one parent Table (Project) that has about 15 child
> tables associated to it logically. The developers of this application
> created 2 triggers to handle the Insert and Delete anomalies whereas 30
> constraints would had to have been coded.
>
> From a performance perspective, what are the ramifications for this
> design decision? How expensive is a constraint compared to a Trigger?
>
>
> Thanks.
>
Received on Fri Jul 26 2002 - 17:16:51 CDT