SELECT MAX() vs Oracle_SID
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Thread: SELECT MAX() vs Oracle_SID

  1. #1
    Join Date
    Jul 2001
    Posts
    1

    Question

    I have an Oracle backend for an ASP application. I want to know about using SELECT MAX vs using Oracle_SID. I'm particularly interested in issues of concurrent users inserting records. From an SQL statement standpoint, SELECT MAX is easy to use. If I were to use Oracle_SID, what would be the steps involved? Would I have to create a pre-insert trigger for the Oracle_SID? How does this effect the SQL INSERT statement? Does the trigger handle creating the PK Index entry or do I still have to account for it in the SQL statement? Thanks!

  2. #2
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
    Posts
    9,092
    Not really sure where ORACLE_SID comes in, but I am guessing you are referring to a sequence. Using SELECT MAX() poses one big problem with multi user apps; you can't GUARANTEE that two users won't get the same result for MAX(). This would lead to identical PK values.

    The best solution is to use a BEFORE INSERT trigger and let the trigger pick a value off the sequence and insert that value into the table.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
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