Null Query Test

[Peter.Greulich]

How do you test for a query returning a null value using the form.load method? The follwoing script does not work:vClient_ID = CLIENTS->CL_ID

f = :Form.load("ContactsDialogView","Dialog")
f:TABLES:CONTACTS.filter_expression = "between(CL_ID,'"+vClient_ID+"','"+vClient_ID+"')"
f:tables:Contacts.order_expression = "Last+First"
Q = f:tables:Contacts.query()

nrecs = Q.records_get()
IF nrecs = 0
Q.drop()
vChoice = ui_msg_box("Contacts Warning","There are No Contact Records" + CHR(13) +
"Do you wish to create a new Contact?",UI_QUESTION_SYMBOL+UI_YES_NO)
IF vChoice = UI_NO_SELECTED
GOTO CLOSING
ELSE IF vChoice = UI_YES_SELECTED
'misc. code here
END IF
end if

CLOSING:
f.close()
END

[Tom Cone Jr]

RE: Null Query Test

Peter, I don't see any obvious problems with your script. What does 'does not work' mean, specifically?


Is it possible the filter expression isn't seeing the variables? Does each variable need to be prefixed with 'var->' ?


Is your form based on a set or a table? Are you trying to query a field which is used to set the order in your set (like I was doing yesterday in a different message thread...)


-- tom

[Geoffrey Hollander]

RE: Null Query Test

Hi Peter,

I have an application that requires the user to query quite often. Many times the query run is simply to see if any records qualify, or not.

When it's time for a user to run one of these, a UI_GET_EXPR() box pops up and asks for the query expression. The results of this expression are saved in the global memory variable, "q_filter". (There is also another UI_GET_EXPR() box that pops up for the user when he/she wants to sort, requesting a sort expression; saved in the memory variable, "q_order".) Once the query has been run, the following code checks to see if any records were selected and if not, shows the UI_MSG_BOX() shown below and resets the unsuccessful query with a generic one that brings in all the table's records in record order:

' THIS IS THE QUERY STATEMENT, USING THE GLOBAL MEMORY VARIABLES MENTIONED ABOVE:

query.order = q_order
query.filter = q_filter
query.options = ""
tbl.query_create()

' THIS CODE CHECKS TO SEE IOF ANY RECORDS WERE RETRIEVED:

findrec = tbl.query_create()
recs = findrec.records_get()

IF findrec.records_get()

[Finian Lennon]

RE: Null Query Test

Peter:

The following will work:

Q = f:tables:Contacts.query()
idx=f:tables:Contacts.index_primary_get()
nrecs = idx.records_get()

Finian

[Peter.Greulich]

RE: Null Query Test

Thanks Finian, that does the trick.
Thanks Geoff, I will have to study your script a little.

[Peter.Greulich]

RE: Null Query Test

The form loads but the script halts DOA.
Finian's answer below solves the problem.