The World of Computer Software/World_Of_Computer_Software-02-387-Vol-3of3.iso/a/ac-notes.zip/ACCBUG.TXT

Text File | 1993-02-19 | 22KB | 509 lines

The following list identifies problems that may occur when using
Microsoft Access.  This list contains all significant, reproducible
problems that we have found since releasing the product.  The list
will be updated on a regular basis as new problems are identified and
validated.  If you have recently reported a bug which is not on this
list, then it is most likely in the process of being researched and
validated.  A detailed description of each problem and the suggested work
around is also provided below.  (2/19/93)

1.  Incorrect Windows For Workgroups driver can cause file truncation
    (correct driver included with Microsoft Access)
2.  Incorrect LAN Manager driver can cause file truncation (correct
    driver included with Microsoft Access)
3.  Microsoft Access SETUP may have problems with DOS APPEND statement
    in Autoexec.bat
4.  ATI Ultra video driver not compatible with Microsoft Access
5.  Microsoft Access SETUP may leave temporary directory and files on
    disk
6.  Problem importing .DBF files where record length exceeds dBASE
    maximum
7.  Microsoft Access cannot use Btrieve data with indexes across column
    boundaries
8.  Fixed Width import does not correctly translate extended characters
9.  Cannot hide modal/popup forms with the OpenForm action
10. Form dynaset references do not always work when using form variables
11. Problem using Running Sum property with control that evaluates to
    #ERROR
12. Beta versions of ODBC drivers will not work with Microsoft Access
13. STACKER 3.0 incorrectly reports that database files are corrupted
14. Cannot use the CVDate and IsDate functions with empty string argument
15. Cannot declare new form object variable during break mode
16. Cannot attach to foreign database in multi-user environment
17. Using LIKE with trailing spaces and wild cards will not work properly
18. Query with descending sort on indexed duplicate data can return
    incorrect results
19. Cannot add counter columns to existing tables with large amounts of
    data
20. Fixed Width Import does not work with variable length records
21. Searching on Paradox data with multi-column indexes that contain
    NULLS
22. Update Queries do not work with "Restrict Available Fields" Option
    disabled
23. Using the BTRIEVE NLM may give an undefined error alert
24. Duplicate values may be returned on "Unique Values Only" queries
    (DISTINCT)
25. Microsoft Access may have problems when multiple instances of
    extremely large query definitions are used



1. Incorrect Windows For Workgroups driver can cause file truncation
(correct driver included with Microsoft Access)

NOTE:  This problem was discovered before Microsoft Access was released
and all copies of Microsoft Access include the updated Windows for
Workgroups driver and installation instructions.

DESCRIPTION:  If you have an early version of the Windows for Workgroups
WFWNET.DRV file (before 11-02-92), using the Network button in Access
dialog boxes to connect to password-protected servers may cause any
database files that you open on that server to become truncated.

WORK AROUND:  Update the WFWNET.DRV driver file using the driver update
program included with Microsoft Access.  Complete instructions are
contained in the flier included in your copy of Microsoft Access.


2. Incorrect LAN Manager driver can cause file truncation (correct driver
included with Microsoft Access)

NOTE:  This problem was discovered before Microsoft Access was released
and all copies of Microsoft Access include the updated LAN Manager driver
and installation instructions.

DESCRIPTION:  Using Microsoft Access on a Microsoft LAN Manager
workstation (prior to version 2.2) can cause files to become truncated.
Products that may be affected include: Microsoft LAN Manager prior to
version 2.2; DEC Pathworks for DOS version 4.1; NCR StarGroup LAN Manager
version 3.6; Olivetti Olinet LAN Manager version 2.1; Ungermann-Bass
LAN Manager version 2.1.

Database truncation is most likely to occur when a user workstation
operates faster than the file server on which the database file is stored.
(Note that the CPU speed alone does not determine the operation speed of
the server. Heavy network traffic can make the server operate more slowly
than a user workstation(s).)

WORK AROUND:  If you have LAN Manager 2.1 or 2.1a, install the LAN Manager
Hotfix included with Microsoft Access appropriate to your version of LAN
Manager.  If you have LAN Manager 2.0, include the appropriate line in your
LANMAN.INI file for LAN Manager versions prior to 2.1.  Refer to the
instructions included in the README.TXT file in your Microsoft Access
package for complete details.


3. Microsoft Access SETUP may have problems with DOS APPEND statement in
Autoexec.bat

DESCRIPTION:  If you have an APPEND statement in your AUTOEXEC.BAT file
and that APPEND statement defines a path where other README.TXT files
exist, Microsoft Access SETUP may abort when installing the README.TXT
file.

WORK AROUND:  Remove or remark out the APPEND statement in your
AUTOEXEC.BAT file and reboot your computer before trying to setup
Microsoft Access.


4. ATI Ultra video driver not compatible with Microsoft Access

DESCRIPTION:  Using ATI-supplied drivers included with the ATI Ultra video
card can cause any of the following problems in Microsoft Access: 1)
General Protection Fault on disabled cascading menus (most common case is
Layout menu with Align command disabled in form or report design); 2)
disabled buttons not visible; and 3) text alignment problems.

WORK AROUND:  The suggested work around for these problems is to use the
8514 video drivers included with Windows 3.1 and not the video drivers
supplied with the ATI Ultra video card.  NOTE: Microsoft is working with
ATI on this problem.  We will post more information on this forum as it
becomes available.


5. Microsoft Access SETUP may leave temporary directory and files on disk

DESCRIPTION:  If you request SETUP to install SHARE and then choose the
option to reboot your machine at the end of the installation process,
SETUP will not properly clean up temporary files on your hard disk.  This
leftover directory will have the name MS-SETUP.T and will contain data
files totaling approximately 600K.  Besides taking up hard disk space,
these files will have no affect on Microsoft Access or any other
applications.

WORK AROUND:  Do not choose to reboot your machine at the end of the
installation process or simply delete the files and directory after the
reboot process.


6. Problem importing .DBF files where record length exceeds dBASE maximum

DESCRIPTION:  CodeBase ++ v1.07 allows you to create .DBF files where the
record length exceeds the dBASE IV maximum.  Microsoft Access may hang
when trying to import these type of .DBF files.

WORK AROUND:  Export the CodeBase++ .DBF file to delimited text, then
import the ASCII file into Microsoft Access.


7. Microsoft Access cannot use Btrieve data with indexes across column
boundaries

DESCRIPTION:  Microsoft Access will display the error message: "File is
corrupt or isn't an Access file" when attempting to attach or import a
BTRIEVE file which has an index defined across a column boundary."

Access does not support BTRIEVE indexes which have keys defined on a
partial column or across column boundaries.  Indexes which have a segment
of the key which is defined to cross a column boundary are not supported
by the Xtrieve data dictionary format.  Xtrieve may ignore these indexes
and import the file correctly but Microsoft Access does not.

WORK AROUND:  You must remove the indexes or recreate them so that they
align on column boundaries.


8. Fixed Width import does not correctly translate extended characters

DESCRIPTION:  When importing a Fixed Width ASCII file, Microsoft Access
does not properly translate extended characters from OEM to ANSI
representation.  The first 4K of data is imported and translated
correctly, but all data after the initial 4K will not translate correctly.

WORK AROUND:  Convert the ASCII file from OEM to ANSI using another
Windows application, such as Windows Write.  Using Windows Write, simply
open the file, responding 'Yes' to the convert alert, then save the file.


9. Cannot hide modal/popup forms with the OpenForm action

DESCRIPTION:  Using the OpenForm action to hide a modal/popup form may
cause a General Protection Fault.

WORK AROUND:  Hide a modal/popup form by using the SetValue action to set
the forms .Visible property to False.


10. Form dynaset references do not always work when using form variables

DESCRIPTION:  If you reference a form dynaset with variables, you may
receive a General Protection Fault.

WORK AROUND:  Always refer to a form dynaset with explicit references
through the form.  The first code fragment below shows how to references a
form dynaset safely and the second code fragments shows what will most
likely cause the problem.

A)     SAFE:
       forms!testform.dynaset!col1="foo"

B)     MAY CAUSE PROBLEMS:
       dim f as form
       set f = form!testform
       f.dynaset!col1 = "foo"


11. Problem using Running Sum property with control that evaluates to
#ERROR

DESCRIPTION:  If a report contains a control where the Running Sum
property is set to 'Over Group' or 'Over All' and the control evaluates to
#ERROR, Microsoft Access will cause a General Protection Fault.

WORK AROUND:  Correct the expression in the control source property so
that it evaluates correctly.


12. Beta versions of ODBC drivers will not work with Microsoft Access

DESCRIPTION:  When using Beta versions of the ODBC drivers, Microsoft
Access may experience General Protection Faults in ODBC.DLL.  The problem
is that when Microsoft Access initiates an ODBC connection, ODBC does not
properly check the version of the ODBC driver.

WORK AROUND:  Rename or delete the beta version of ODBC.DLL and run the
ODBC setup program from the setup disks that come with Microsoft Access.
This will install a current ODBC.DLL file.


13. STACKER 3.0 incorrectly reports that database files are corrupted

DESCRIPTION:  Running Stacker's "check /=D /F" command will often report
that some Access .mdb files are corrupt and should be deleted.  The
problem is that the "/=D /F" flags are for development and debugging
purposes and will report things which are really not problems.  If for
some reason you run CHECK.EXE with the /=D switch and it asks if you want
to delete a file, answer NO!  The file is fine.  These are superfluous
error messages.

WORK AROUND:  Do not run CHECK.EXE with the /=D switch.  If you do run
CHECK /=D, answer NO when prompted to delete files.  Stac Electronics has
written a document explaining the "Lost Sector Groups" reported by CHECK
/=D.  The document is referenced as TEC042.DOC on CompuServe or the Stac
BBS and as document #3003 on STAC FAX, Stac Electronics' automated FAX
response service.


14. Cannot use the CVDate and IsDate functions with empty string argument

DESCRIPTION:  The CVDate function is used to convert a string or numeric
expression to a variant of type date.  If this function is called with the
empty string as the expression (i.e. CVDate("")) then you will get a
general protection fault.  The IsDate function has the same problem.

WORK AROUND:  Verify that you are passing valid date strings in the
argument to CVDate.


15. Cannot declare new form object variable during break mode

DESCRIPTION:  The General Protection Fault occurs when declaring an object
variable (form, table, etc.) during break mode (when debugging Access
Basic code) and then trying to recompile the code. The following are
examples of object variable declarations:

  Dim F as Form
  Dim T as Table

WORK AROUND:  Don't add these type of variables while in break mode.


16. Cannot attach to foreign database in multi-user environment

DESCRIPTION:  Attaching/importing will only work if you can open the
foreign database file (dBASE, Paradox, BTRIEVE, etc) exclusively.  If you
attempt to attach to these types of files while others are using them you
will get an error message stating that the table or file is already in
use.  This problem is isolated to attach and import.  Once you have
successfully attached to a file of this type you can then edit or browse
this file in a multi-user environment.

WORK AROUND:  Must obtain exclusive access to foreign database file in
order to import or attach.


17. Using LIKE with trailing spaces and wild cards will not work properly

DESCRIPTION:  When using the LIKE operator with trailing spaces and
trailing wild cards (i.e. LIKE "The *") you will not always get back the
proper results.  Access ends up trimming the trailing spaces in this case
and actually performs LIKE "The*".  This is only a problem when you have
both trailing spaces and the trailing wild card character.

WORK AROUND:  A sample work around for the LIKE "The *" example would be
as follows:

     (LIKE "The*" AND (mid$([Field],4,1) = " "))


18. Query with descending sort on indexed duplicate data can return
incorrect results

DESCRIPTION:  When sorting data in descending order on a column that is
indexed and contains over 506 duplicate entries, Access can return
incorrect results to the user (wrong number of rows).  This can occur when
the Index property for a column is set to Yes (No Duplicates) or Yes
(Duplicates OK), but not when there is a primary key on the column.
Non-primary key indexes can have multiple NULL entries.

WORK AROUND:  Remove the index from the column that is being sorted.  This
will cause the query to execute more slowly but will give you the correct
results.


19. Cannot add counter columns to existing tables with large amounts of
data

DESCRIPTION:  You cannot add counter columns to an existing table that
contains large amounts of data (roughly anything greater than 4 MB of
data).  This problem occurs because of a current limitation in the Access
transaction model (transaction size limited to 4 MB).  This problem
manifests itself with counter columns because the table data for this
column is updated as the column is added.  This update will take place
within a transaction and on large tables it will encounter the Access
transaction size limit.  The transaction will then rollback and the
counter column will not be successfully added.

WORK AROUND:  Follow these steps to add a counter column to a large
table:

  1) Copy/Paste the table structure (not the data) to a new table
  2) Add a counter column to this new table
  3) Create an append query that transfers data from the
     old table into the new table
  4) Verify new table has correct data
  5) Delete the old table
  6) Rename the new table to the name of the old table


20. Fixed Width Import does not work with variable length records

DESCRIPTION:  The fixed width import utility currently expects all records
in your text file to be the same length.  This most commonly presents
itself as a problem when the right most column of your text file has
strings of different lengths and they are not padded with spaces.  In this
case, Access will not import the data as you might expect (Access will
look to the next line for more characters if the right most column is not
properly padded).

WORK AROUND:  When importing ASCII Fixed Width files you must ensure that
all record (lines of text) are the same length.  In some cases this may
require that you manually or programmatically pad some lines with the
correct amount of spaces.  The following piece of code below is an example
of how one might programatically pad the lines of a text file so that all
lines (records) of the file are fixed length.

'----------------------------------------------------------------
'InFile$  - name of Fixed Width Ascii data file
'OutFile$ - name of new file to create with proper padding
'RecLen%  - Fixed length of each record in the padded file
'----------------------------------------------------------------
Sub PadFixedWidthFile (InFile$, OutFile$, RecLen%)

  fh1% = FreeFile
  Open InFile$ For Input As #fh1%

  fh2% = FreeFile
  Open OutFile$ For Output As #fh2%

  'Pad data and place in new file
  While Not EOF(fh1%)
    Line Input #fh1%, Ln$
    If (Len(Ln$) < RecLen%) Then
      Ln$ = Ln$ + String$(RecLen% - Len(Ln$), " ")
    Else
      MsgBox "Padding process aborted! - Data exceeds record length "
      MsgBox Ln$
      GoTo ExitPadFixedWidthFile
    End If
    Print #fh2%, Ln$
  Wend

ExitPadFixedWidthFile:
  Close #fh1%
  Close #fh2%

End Sub


21. Searching on Paradox data with multi-column indexes that contain NULLS

DESCRIPTION:  Using the Edit Find dialog to search Paradox fields for
specific values will not work properly if the field being searched is part
of a multi-column index, the field contains NULLS, and the "Search Fields
As Formatted" option is disabled in the EditFind dialog.

WORK AROUND:  The workaround is to check the 'Search Fields as Formatted'
option so that the index is not used in the search.  Similarly, when
querying on Paradox fields that are part of a multi-column index and
contain NULLS you should use the LIKE operator in places where you might
normally use the equivalence operator.

AVOID:
   SELECT *
   FROM TestTable
   WHERE ((FieldX=23));

WORK AROUND:
   SELECT *
   FROM TestTable
   WHERE ((FieldX Like 23));


22. Update Queries do not work with "Restrict Available Fields" Option
disabled

DESCRIPTION:  If you use the View Options dialog to set the Query Design
option "Restrict Available Fields" to NO (the default is YES) then UPDATE
queries will not work correctly.  In the most common case Access will
cause a General Protection Fault, but there have been isolated cases where
the query actually executed to completion and incorrectly altered the data
in your table (the wrong columns get updated).

WORK AROUND:  Use the Query Properties dialog to set the "Restrict
Available Fields" option to No on a query by query basis when this
functionality is desired. Do not use the View Options dialog to set
this option on a global basis.


23. Using the BTRIEVE NLM may give an undefined error alert

DESCRIPTION:  Users who do not have all of the correct versions of
BREQUEST.EXE, WBTRCALL.DLL, and WBTRVRES.DLL may receive an "Internal
Database Error (-5001)" alert when using the BTRIEVE NLM.

WORK AROUND:  In order to get the BTRIEVE NLM to function properly, we
recommend that the NLM requester (client) uses the 6.0 versions of
BREQUEST.EXE, WBTRCALL.DLL,  WBTRVRES.DLL and the 5.15 version of
BTRIEVE.NLM. Follow these steps:

  1) Sign on to CompuServe
  2) Go NOVLIB
  3) Go into the BTRIEVE/XQL library section
  4) Download the BT515.ZIP file
  5) Use PKUNZIP.EXE to unpack the file
  6) Unpack the BTRREQ.ZIP file that gets unpacked from step 5
  7) Obtain the following files:
      WBTRCALL.DLL
      WBTRVRES.DLL
      BREQUEST.EXE
  8) Follow the readme notes to properly install and execute these files
  9) The readme should also explain how to apply patches 1-65 to the
     BTRIEVE.NLM file on the server

The WIN.INI file should also be modified with the following lines:

[BREQUESTDPMI]
datalength=4096
tasks=10
local=no
chkparms=no


24. Duplicate values may be returned on "Unique Values Only" queries
(DISTINCT)

DESCRIPTION:  DISTINCT queries may return a few duplicate values at the
beginning of the result set if the data set is very large.  This happens
only if the result set of the query is greater than 64K (counting the
duplicate values).  Record position of the duplicate values in the result
set is a contributing factor.

The conditions that must be met are as follows:

a) The underlying table(s) contains a large number of records (the result
   set must be >64K).
b) The data values that sort to the beginning of the output must have
   many duplicate values scattered throughout the input.

This can manifest itself in a Select query with the Unique Values Only
property turned on (DISTINCT).  It can also show up in a Crosstab query as
duplicated columns with names like "Field0", "Field1", etc.

This problem only occurs with Select DISTINCT queries, and not with the
much more common Select DISTINCTROW queries.

WORK AROUND:  For Select queries, use Totals with GROUP BYs instead of
using the Unique Values Only property.

For Crosstab queries, use Fixed Column Heading to prevent the problem.


25. Microsoft Access may have problems when multiple instances of
extremely large query definitions are used

DESCRIPTION:  Trying to open more than one instance of a query may cause a
General Protection Fault in Microsoft Access when the query definition is
extremely large.  For example, if you have a form based on a query with a
query definition size of >32K and you then attempt to create a SnapShot
from the same query, Microsoft Access may cause a General Protection
Fault.  This happens because multiple versions of the query definition
must be saved, and the saved query definitions do not fit within the
query's segment space (the space allocated to each query).

Note: The number of records in the result set is NOT a contributing factor.

WORK AROUND:  Create a second query based on the first query and use one
of the queries for the form, and the other query for the SnapShot.