View Full Version : using WAS session variables as part of filter


08-05-2004, 10:16 PM
Hi. I want to display part of a table using a grid component. The table, however, is moderately large (10,000 or more records), and even though I only need to display a few records, the grid component feels obligated to prepare to display all the records. This takes a few seconds.
What I want to do is to start by displaying only the records of interest. So I have a dialog component, which asks for a date of interest, and then the AfterValidate event of the dialog component does something like
where "searchdate" is the date entered in the dialog component.

Now, in the second component, I want to set the filter in the Query property of the grid component to be
between(date, session.startdate-2, session.startdate+2)

This should display only a few days before and after the starting date; so instead of having 10,000 records for the grid component to work with, it only has to work with 20 or 30.
Problem: the filter for the query does not recognize the above filter as valid. What it looks like I have to do is to is to create a table-level variable and then I can use a filter, but this seems roundabout. Is there a way for the grid filter to recognize what the WAS's "session" pointer is?
- Peter

08-06-2004, 04:17 AM

You can add the filter outside of the component. I found the easiest way is to set up some basic filter for the componet when designing with the component builder. Then look at the xbasic code in the builder where the filter is set. For example, in one of my test components, I find

tmpl.DBF.filter = "Course_Id ""\"\""

Then on the actual page where I run the component, I reset the filter to whatever I want after the component is loaded. For example, something like this is created when the component is added to the page

tmpl_CourseInfo = a5w_load_component("CourseInfo")

Then to change the filter, I use this after that

tmpl_CourseInfo.DBF.filter = "Course_Id=\""+courseid+chr(34)

In this case, course_id is a local variable, but it could be a session variable.


Selwyn Rabins
08-06-2004, 06:29 AM
jerry's response is correct.
in fact, you can override almost any of the component's properties in the page after the component has been loaded. (you need to switch to source view).

if you look at the source view, you will see that all components are loaded with code like this:

DIM Tmpl as P
tmpl = a5w_load_component("component_name")
with tmpl
componentName = "component_alias"
end with

so, to override the dbf.filter property, you would do this:

DIM Tmpl as P
tmpl = a5w_load_component("component_name")
with tmpl
componentName = "component_alias"
dbf.filter = "new_filter"
end with

however, even if you choose not to override the dbf.filter property, when the page loads, it only displays 10 rows. so it should not really matter how many records the table has in it.

08-06-2004, 07:27 AM
Thanks to both of you. I wasn't sure at what point to stick in code to override the template settings to start displaying at the mid-point or the end of the table, rather than the beginning each time.
It had been my impression that the web server is slower displaying records from a large table; I guess I was wrong, and that it doesn't matter whether there are 100,000 records or 20 records in the table?

Selwyn Rabins
08-09-2004, 07:01 PM
if there are 100,000 records and your query is such that LQO can be used, then it should not matter. however, if LQO can not be used, then it would be slower to display a grid that was based on a table with 100,000 records.