We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you two Citrix podcasts. Learn about 2020 trends and get answers to your biggest Citrix questions!Listen Now

x

Queries and Cached Updates

jeisen
jeisen asked
on
Medium Priority
157 Views
Last Modified: 2010-04-04
I run a query to select rows from a table (just one!)
based on user input. I then need to print the data from the selected rows.
The order is important, so I use an Order By clause which prevents me from
setting the RequestLive property to true. Finally, after each row is
printed, I mark the row as printed along with the date. This is important so
that if there is a printer error or other problem, the user would only need
to reprint from where they left off. The code is as follows:

1.    query the table
Select * from customertable where customernumber = :customernumb
2.    process the result
try
   Query1.Open;
   While not Query1.eof do
      begin
           PrintRoutine(Query1);
           Query1.Edit;
           Query1.FieldByName('DATEBILLED').Value := Date;
           Query1.FieldByName('ACTCODE').Value := 3;     (***marks the row
as printed**)
           Query1.Post;
           Query1.Next
      end;
except
   showerror
end;
3. update the rows as printed
MyDatabase.ApplyUpdates([Query1]);

At the MyDatabase.ApplyUpdates([Query1]) line I get an application error
with the message table is read only. I thought that is why you use a
TUpdateSQL component! I don't know if this helps you understand my problem
better or not. I have been struggling with this for awhile and would
appreciate any help. I am using Delphi 2.01 with a Paradox table.

Jay Eisenstock

Comment
Watch Question

zac

Commented:
What is the contents of your UpdateSQL objects' modify property, and what are the key fields in the database?

Author

Commented:
In response to the question about the UpdateSQL Property:
update CustomerTable
  ACTCODE = :ACTCODE,
  DATEBILLED = :DATEBILLED
where
  CUSTOMER = :OLD_CUSTOMER

I used the update SQL editor to generate the code. The key fields are CUSTOMER and CODENUMBER.
Cached update's is not supported for local table's like Paradox.
I think you should use a second query, whith an update statement for the customertable.
You can build this dynamicly with the values you read form your query1. In the where clause you use the primary key from query1. After this you have to reopen Query1 to see the results in this query.

Hope this helps.

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts

Author

Commented:
I graded the answer C because I found a better solution. Here it is:
1  Change the original query to eliminate the "order by" clause and set "RequestLive" to true
2  Batch copy the query to a temporary table indexed by the values in the original "order by" clause
3  Process through the indexed table sequentially to print each value. Then, do a Locate on the query to update the values
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.