On the fly reengineering of database schema

From: Øyvind Harboe (oyvind.harbo..ylin.com)
Date: Fri Jul 20 2007 - 14:42:34 EDT

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    Currently our Cayenne app has the database field size and types stored
    in the configuration files that ship with the application. They were
    generated in the Cayenne modeler.

    Is there any reason, in principle, why we couldn't read that info
    during startup of the application? IOW, reengineering on the fly.

    - It would allow database maintainers to adjust field sizes without us
    updating Cayenne.
     We have a lot of variants of the database schema in the field and
    changing size of a NVARCHAR or changing an NVARCHAR to a CLOB would
    be typical operations.
    - Adding a field to a database table could be done from the database GUI
    - We would be able to cope easily with the absence or presence of
    optional table fields

    The Cayenne modeler would still be useful to choose Java
    representation of the fields regardless of their type(CLOB, NVARCHAR,
    CHAR, etc.).

    We have some database adapters that don't do robust reengineering
    (FoxBase, MS Access, shudder!), but presumably we could
    programatically adapt the Cayenne database schema for those/stick with
    a default one which we do today.

    -- 
    Øyvind Harboe
    http://www.zylin.com - eCos ARM & FPGA  developer kit
    



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