OAUG Meeting November 95

Questions



System Error after running a compiled application

Keith O'Donnell raised a problem where OA reported a system
error "Unimplemented p-code" when he tries to "Quit" Open Access
4. It only occurs after a compiled application has been run and
he returns to the main options menu. OA is installed for a
Netbios environment on a Lantastic network.

It was suggested that he checks that the check version of
NETBIOS.COM is being used to run the network.

Database Table with corrupted decimal field

A database table appears to have corruption in a decimal field.
Fix-file and Resize do not appear to work. Neither does deleting
the *.IF file and Resizing (after copying another dummy file to
the *.IF file).

It was suggested that doing a Query on the database table then
Updating the field with the expression fieldname*1.0  could fix
the problem.

Another possibility is exporting the file to DIF or dBase then
importing it back into OA. Note that the DIF export loses memo
fields and the dBase export converts integer and time fields to
decimals.

A further suggestion was to use Design/Modify-file to set all
fields to non-key, save the changes then use Design/Modify-file
to set key fields again.

Direct faxing from OA

We would like to hear from anyone who successfully sends faxes
directly from Open Access. This would probably involve software
such as Bitfax for DOS which can be set up to emulate a printer
and defining a printer with the appropriate 64 impossible
questions under Open Access. 

The System Manager operating system comes with faxing facilities.

Reading bank statements in ASCII format

A user wishes to convert relevant lines in the ASCII file of a
bank statement into database table records. The OA file
converter does not work because some lines contain invalid data.

This can be done under Programmer. See the INPUT , EXTRACT and
POS commands for examples of reading ASCII files line by line.
The general method, in a loop, is:

Read the next line (READLINE!)

Using EXTRACT, test whether it contains valid data

If the line is valid generate a NEW database table record

Using EXTRACT & VAL, assign values to the fields in the database
table record

INSERT the new database table record



To test if a string contains a valid numeric value before using
VAL you can test some or all letters with code such as

	s1 = EXTRACT(s2,1,1)

	IF s1>='0' AND s1<='9'

                va.amount = VAL(s1)

	END IF





Limitation on comparing fields from different fields in an SQL
join

When you use an SQL to retrieve joined database records it is
useful to be able to compare fields in the two databases.
Unfortunately the Open Access database engine only allows = or
<> (not equal to) to be used. Less than or greater than tests
will not work. For example

	FROM file1,file2 WHERE chqnum=file2.chqnum and file1.amount <
file2.amount

will not work.. In this case you might need to create an extra
working field and use Update to calculate the difference between
file1.amount and file2.amount.

Imbedded quote in print mask items

The OA print mask uses the double quote " to identify virtual
fields. "vf":sum(amount) creates a virtual field called vf with
a value equal to the sum of the database table field amount. The
virtual field can then be used in subsequent expressions.

This facility causes problems when you need a single quote in a
print mask item - for example TERRY'S PHONE LIST. If you try
enclosing this in double quotes you will receive an error
message. The trick is to use an expression which does not start
with a double quote such as:

'' + "TERRY'S PHONE LIST"     (<single quote><single
quote><plus> <double quote> etc)

Running OA under Windows for Workgroups (from DOS or Windows)

Open Access can be installed for a Netbios network under Windows
for Workgroups. Also the peer-to-peer networking facilities
which come with Windows for Workgroups can be run from DOS,
without Windows. See the NET command in the Windows manual for
details.

Segmenting Compiled Programs

Keith O'Donnell reported that he has found the method of
segmenting compiled programs can make a big difference to
response times over a network. Each time a segment is called the
local CPU must read the appropriate "overlay" from the APP.SPI
file which is on the fileserver. This can be 400K or more and it
can cause delays. Our advice is avoid imbedding a segment call
within a loop. For example if your code is of the form:

	WHILE RECNO(va) > 0

		DO calc_av

		FIND va next

	END WHILE

make sure that the code for calc_av is in the same segment as
the calling routine.

Multiple joins to the same database table within a print mask

It is common practice to include the names and addresses of all
clients of a business in one database table. This can include
suppliers and customers. A problem arises if you wish to create
a print mask which uses more than one record from the CLIENT
database table. An example might be a JOB database table which
has two "must match" fields  linked to the CLIENT table. The
first field might be the customer number and the second field
might be the supplier number. In order for the print mask to be
able to use the correct data the SQL needs to have an Alias
assignment. The SQL might look like this:

FROM JOB,CLIENT,T=CLIENT

WHERE JOB.CUSTOMER=CLIENT.CUSTNUM AND

JOB.SUPPLIER=T.CUSTNUM

and the print mask can contain the alias fields:

	Suppler: [job.supplier] - [t.name] [t.phone]

See the reference to Aliases in the Database Reference Manual
for more information.





News from SPI

Lindy spoke to John Bowne from SPI in San Diego. He seemed
enthusiastic about developments with SPI products. 

Windowbase 2.02 has just been released (bug fixes??) but there
is no runtime version at this stage.

OA 4 "plus" is under development following a push for extra
features from Europe

Distributors are being appointed in Spain, Italy and maybe France

SQL Access (or similar product) is being enhanced to cover
additional database structures - perhaps including Oracle.

US Department of Defence has a "site licence" for over 400,000
users!

We are waiting for more details about these initiatives from SPI.