merging oracle databases
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  1. #1
    Join Date
    Feb 2003
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    4

    Smile merging oracle databases

    Hello,
    Hope you can help me. I need to know how is it possible to merge 2 oracle databases together. Both databases have exactly the same tables and objects.
    Here is the scenario. One database is the production server database which is used in a multi-user environment. I have some users that need a copy of this production database on their laptops, to be updated every week so they can use it in the field. Is it possible to import a full dump of the production db to the local databases on their machines and merge the data with last weeks data..and so on?
    Or, do i have to always create a new blank database on the laptops and import the latest dump and dispose of the local db of last week?
    This would be too much work.
    I really am trying to find a way of synchronising the databases.

    Thanks for you help.

  2. #2
    Join Date
    Mar 2002
    Location
    Mesa, Arizona
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    This is a classic problem and it's usually handled by importing to temporary tables, then merging with some smart code (eg. pl/sql package, sql script)

    Do you have primary keys on these tables?

    Consider how you would handle duplicates and how you would handle who wins when there is a duplicate key.

    Do you have timestamps on the table's rows?
    "I do not fear computers. I fear the lack of them." Isaac Asimov
    Oracle Scirpts DBA's need

  3. #3
    Join Date
    Aug 2002
    Location
    Atlanta
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    in 9i there is the merge command that does an update if the row exists or an insert if the row does not

    steve
    I'm stmontgo and I approve of this message

  4. #4
    Join Date
    Oct 2002
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    Breda, The Netherlands
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    You need "Disconnected Snapshot Replication" for this problem

    Follow this link for the documentation: http://download-west.oracle.com/docs...ter_.htm#33063

    There you'll find (for instance):

    Support for Disconnected Snapshot Environments
    Snapshot replication allows users to remotely store all or a subset of replicated data from a master site in a disconnected environment. This scenario is typical of sales force automation systems where an individual's laptop (a disconnected device) stores a subset of data related to the individual salesperson.

    Happy reading!

    HTH,
    Erik
    Last edited by efrijters; 09-16-2003 at 03:02 PM.
    An expert is one who knows more and more about less and less until he knows absolutely everything about nothing.

  5. #5
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    Mar 2002
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    Excellent ideas!

    Just curious, how do Disconnected Snapshot Replication and MERGE handle key duplication?
    "I do not fear computers. I fear the lack of them." Isaac Asimov
    Oracle Scirpts DBA's need

  6. #6
    Join Date
    Feb 2003
    Posts
    4
    Thanks for the replies guys. All tables have referential constraints and most have timestamps. However, we are talking about over a hundred tables here. Thanks. I have Oracle 8i by the way.

  7. #7
    Join Date
    Oct 2002
    Location
    Breda, The Netherlands
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    317
    Originally posted by KenEwald
    Excellent ideas!

    Just curious, how do Disconnected Snapshot Replication and MERGE handle key duplication?
    Maybe you can avoid a conflict by giving each representative a different start value in their sequences?

    Code:
           SEQUENCE 
    REP.   STARTS AT
    John     1000
    Mary     2000
    Dick     3000
    An expert is one who knows more and more about less and less until he knows absolutely everything about nothing.

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