Corrupt Error Message with Attached Btreive Table 

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The information in this article applies to:

 - Microsoft Access version 1.0
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Summary:

SYMPTOMS
   When you try to attach to a Btrieve table you receive the following
error message:

      <tablename> is corrupted or isn't a Microsoft Access database.

CAUSE
   When Microsoft Access attaches to a Btrieve table, it compares the
information in the DDF files with the information in the tablename.DAT
file. The most common cause of the above error message is a difference
in the information for the indexes.

RESOLUTION
   The user will need to redefine these indexes in a manner that
Microsoft Access will not return the above error message. The most
common solution is to redefine the index to be the exact length of the
field that it is based upon.

More Information:

Example #1:
-----------

The tablename.DAT file is defined with three columns:

    Column name   Field Length    Index Length
    ------------------------------------------
    Firstname     10              <= Combined length of
    Lastname      10              <= 20 characters
    Company       25

Index1 is defined with a length of 20 characters which combines the
firstname and lastname fields.

Resolution: This index would need to be redefined into one multiply
segment index, each with a defined length of 10 characters.


Example #2:
-----------

The tablename.DAT file is defined with three columns:

    Column name   Field Length    Index Length
    ------------------------------------------
    Firstname     10              4 characters
    Lastname      10
    Company       25

Index2 is defined with a length of 4 characters which is shorter than
the defined length of the firstname field.

Resolution: This index would need to be redefined from 4 characters in
length to 10 characters in length, matching the size of the firstname
field.


Example #3:
-----------

The tablename.DAT file is defined with three columns:

    Column name   Field Length    Index Length
    ------------------------------------------
    Firstname     10              12 characters
    Lastname      10
    Company       25

Index3 is defined with a length of 12 characters which is slightly
longer than the defined length of the firstname field.

Resolution: This index would need to be redefined from 12 characters
in length to 10 characters in length, matching the size of the
firstname field.


Example #4:
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The tablename.DAT file is defined with three columns:

    Column name   Length
    --------------------
    Firstname -   10
    Lastname  -   10
    Company   -   25

Index4 is defined on a numeric byte range and not defined on any
fields in the table.

Resolution: This index would need to be removed completely and then
redefined on an existing field and that has the same defined length as
the field it is based upon.


These types of indexes are valid to the Btrieve file format.  Xtrieve
from Novell simply ignores this type of index.  Microsoft Access
interrupts these indexes as being invalid and returns the above error
message.

How does a user go about changing the index?  The user has several
options:

1. Ask the vendor that created the Btrieve files to change the indexes to
   match the length of the defined fields.

2. Redefine the indexes with Btrieve to match the length of the
   defimed fields.

3. Redefine the indexes with Xtrieve to match the length of the
   defined fields.

4. Use any third party utility that is available to modify the Btrieve
   indexes.