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  1. #1
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    Mar 2004
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    Unanswered: how to modify DBF field datatype

    Hi,
    I wish to change a field datatype from 512 char to a "memo" field in a dbf file (i don't know what version it is).

    1. What software would I need?
    2. Or as an alternative, can someone modify a sample database structure for me so I can test if my theory even works?

    thanks,
    phil

    My theory is that a 3rd party software with updates the .dbf file would continue to work even if i change one of the field datatype from 512 char to memo.

    I'm testing this theory because MSAccess link to this dbf file has a problem with the 512 char field.

  2. #2
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    This gets REALLY complex, due to the limitations of some of the DBF drivers. The change is relatively easy to make, you just need to know which of the "flavors" of memo fields (if any) that the target application can support. The only real advice I can offer is to try a few of the possible formats (I'd usually start with a recent incarnation and work backwards until I found the most recent DBF version that the application would support).

    -PatP

  3. #3
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    Originally posted by Pat Phelan
    This gets REALLY complex, due to the limitations of some of the DBF drivers. The change is relatively easy to make, you just need to know which of the "flavors" of memo fields (if any) that the target application can support. The only real advice I can offer is to try a few of the possible formats (I'd usually start with a recent incarnation and work backwards until I found the most recent DBF version that the application would support).

    -PatP
    I found a program called dbfViewer and it says that the file type of my dbf file is "FoxBase+/dBASE II PLUSE, no memo".

    What software/utility would I need to change the dbf structure?

    thanks

  4. #4
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    Looking at the file won't tell you much. It can tell you the minimum version of software needed to read/write the file, but not what versions of the DBF format are supported by the library used to create the file. You might be dealing with CodeBase which will support nearly every feature that any DBF file can use, or you might be using one of the "bare bones" DBF dump utility libraries that can't even read an NDX file, much less support memos!

    You really need to find out more about the application that is writing the files you want to import. Without knowing that you are striking a match to see how much gasoline is left in the tank!

    -PatP

  5. #5
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    Originally posted by Pat Phelan
    Looking at the file won't tell you much. It can tell you the minimum version of software needed to read/write the file, but not what versions of the DBF format are supported by the library used to create the file. You might be dealing with CodeBase which will support nearly every feature that any DBF file can use, or you might be using one of the "bare bones" DBF dump utility libraries that can't even read an NDX file, much less support memos!

    You really need to find out more about the application that is writing the files you want to import. Without knowing that you are striking a match to see how much gasoline is left in the tank!

    -PatP
    I see. Unfortunately, I won't be able to find out more about the application. I'll just have to modify the table and see if the application continues to work. So back to the old question: What software do I need to modify the dbf field datatype?

    I want to spend the least amount of money to test my theory.

    Thanks,
    phil

  6. #6
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    Depending on which dBase ODBC driver your machine has, Access alone should be able to make the change that you want. Just be careful, you may not get the results that you'd like, and you might well get unexpected changes due to the addition of the memo file... Some applications/libraries get really, really cranky! Make sure you have good backups before you try anything.

    -PatP

  7. #7
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    Originally posted by Pat Phelan
    Depending on which dBase ODBC driver your machine has, Access alone should be able to make the change that you want. Just be careful, you may not get the results that you'd like, and you might well get unexpected changes due to the addition of the memo file... Some applications/libraries get really, really cranky! Make sure you have good backups before you try anything.

    -PatP
    Yes. Your suggestion is about backups is a very good one. You say Access can do this? I've linked the dbase file with Access and it doesn't allow me to change the structure of the linked file.

    Can you point me to where I can get more info on how to do this? Much appreciated. Thanks.

  8. #8
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    I don't use Access much, and I'm bone tired. I'll try to look it up for you tomorrow.

    -PatP

  9. #9
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    Originally posted by Pat Phelan
    I don't use Access much, and I'm bone tired. I'll try to look it up for you tomorrow.

    -PatP
    thank you

  10. #10
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    Lightbulb

    Maybe you can try FOXBASE programs. This program will allow you to create, delete and modify the DBF file.

    Maybe this can help!

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