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  1. #1
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    Is it possible to change the structure of an existing database while keeping all of the current data? Thank you for your time.

  2. #2
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    Welcome to Woody's Lounge!

    But in general it should be possible to preserve your data, but how much work it will be will depend on what exactly you want to do.

    You can:
    - Add fields to an existing table.
    - Change the field size of existing fields in tables, as long as you make sure that the new size is not too small for existing data.
    - Change the field type of existing fields in tables with certain restrictions.
    - For example you can convert a number field to a text field, but usually not the other way round (depends on the data).
    - Add, change and remove indexes.
    - Add, change and remove relationships.

    For more complex modifications, it may be necessary to add auxiliary fields to a table, and populate them using an update query.

    If you want more help, please provide some details about what you want to do.

  3. #3
    4 Star Lounger
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    [quote name='Bonnie' post='794712' date='24-Sep-2009 15:05']Is it possible to change the structure of an existing database while keeping all of the current data? Thank you for your time.[/quote]
    I'd always make a copy of my data, just in case I muck up the structure.
    <IMG SRC=http://www.wopr.com/w3tuserpics/StephenElms_sig.jpg> Didn't think that I made my first post here on 5th February 2001...!

  4. #4
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    [quote name='Bonnie' post='794712' date='24-Sep-2009 08:05']Is it possible to change the structure of an existing database while keeping all of the current data? Thank you for your time.[/quote]
    In addtion to the other comments, when you restructure a database it can have pretty wide ranging impacts. For example, if you decide the database wasn't properly normalized, and you really need to have some of the data in a table spun off into another table that is linked to the first table, that will probably affect any forms or reports that use that data. So restructuring can be a pretty large task.

    However, it is sometimes necessary to really make the database work effectively. That is why we usually spend a fair bit of time up front making sure we understand the problem, and making sure that the schema we set up is appropriate. It's much like pouring a foundation for a house - you want to make sure you have that right before you start putting up studs and such.
    Wendell

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