<Ra******@gmail.com> wrote in message
news:11**********************@i40g2000cwc.googlegr oups.com...
I have just completed a basic course in Access. I have some relational
b/g in DB2 and Cobol. I have a question my instructor couldn't answer
(or maybe I didn't explain myself)
I design a simple form that has data from one table. When I open this
form to display data, are all matching records retrieved into memory
rightaway even though only 1 record is displayed? So when I use
navigation keys to move forward (or back) is data being retrieved from
database or is it coming from memory?
Thanks
A certain amount is retrieved but not all of it. For example, if your table
had 5000 rows in it, then normally you would not want to open a form based
on the unfiltered table. However, if you did, you might be surprised to
find how good performance was. The form will show you that it has 5000
records and you can scroll through them, but behind the scenes, Access is
doing some clever stuff.
If you wanted a test. Create a table with a few hundred rows and save this
back end data. Now create a new datatbase DB1 which has a single linked
table to it. Save and close the file and make a copy of it: DB2. Now you
can open up both front ends so you can see the first 10 or 20 records in the
table. Alter a column in DB1 and move to a new record. Then view DB2 and
notice the screen has not updated. Now go to DB1 and alter the last record.
When you switch back to DB2 and go to the last record - you will see the
same version. Does that make it clear what is happening?