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Re: Database Design: unique PK across all tables

From: <>
Date: Thu, 31 Oct 2002 11:34:19 -0800
Message-ID: <>


As you pointed out, the design of this function will play a rather important part in the performance of this app.

The first thing I would question is the use of this column as a PK. A generated number should be fine. PK's should not carry any information in them, they're just an ID. A series of sequences or any non-serialized method of generating them would be appropriate.

Regardless of whether this function generates a PK or a UK, it needs to be designed to prevent serialization.

e.g. Using a single row table with some kind of counter, or any similar one-at-a-time key generation will really limit the scalability of the app.

HTH Jared

"Brian P Andrews" <> Sent by:
 10/31/2002 05:33 AM
 Please respond to ORACLE-L  

        To:     Multiple recipients of list ORACLE-L <>
        Subject:        Database Design: unique PK across all tables

  Our developers are proposing a database design for an OLTP application in which each table has a PK of the same type and size. In addition, each possible PK value can belong to at most one table.   Each table insert would require a call to the a single function to get the next PK value and an additional table would be used to store the current set of values. (The developers want to put some additional meaning into a PK value and a sequence would not be sufficient, hence the need for the PK generating function and current value table).   I've never seen this done before and I would think this application would suffer greatly from contention when performing a large number of concurrent inserts.
  Has anyone ever encountered a design like this? Is this a bad design?   Thanks.


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