SQL with unbound fields

[PhilM1965]

Hi All,

Here is what I am trying to achieve ...

I have a UX component bound to an MS SQL Server 2008 view. That's all working properly. It's only for display, so no update needed on the tables in the view.

I have some additional unbound fields which relate to another table. All good so far.

Now ... here is where I am having trouble and I just can't get my head around the Alpha way of doing things ... I have a button on the UX which when pressed will write add a new record to the unbound table.

Once this button has been pressed, or when the user enters the UX component, if that record already exists in the unbound table, I want to delete the record. If it doesn't exist, I want to add a new record. The whole UX is filtered by UserName, which is a session variable. Because there could be many records in the unbound table relating to the User, just toggling a flag in the UserName table wouldn't work.

The unbound table consists of four fields :
idPK int, Primary key autoinc
PromotionIDFK, int
DateSaved, date
UserName, varchar(120)

There is also an index on UserName and PromotionIDFK which is unique ... Each UserName can only have one PromotionIDFK.

The bound view has the field PromotionID, int, and UserName, varchar(120) which would be the link for me to relate to the unbound data.

Essentially we have a user who can choose promotions and store them as favourites or delete them from their favourite list.

I guess what I am looking for is the code to click a button to access the unbound table, and if a record is found with the values which match the current username and promotion ID, then display it as being flagged as a favourite, and if not found, then add a new record.

My thinking was varied (or is that random!>) ... for example to write a SQL BEGIN TRY, BEGIN CATCH ... so in pseudocode

BEGIN TRY
INSERT INTO SAVEDPROMOTIONS (PROMOTIONIDFK, DATESAVED,USERNAME) VALUES (UX_IDPROMOTIONSPK, UX_DATESAVED, UX_USERNAME)
CATCH
DELETE SAVEDPROMOTIONS WHERE IDPK = IDPROMOTIONSPK 
END CATCH

But catches all errors that might have caused the insert to fail, not just a duplicate key.

Alternatively, I could do something like

INSERT INTO SAVEDPROMOTIONS (PROMOTIONIDFK, DATESAVED,USERNAME) VALUES (UX_IDPROMOTIONSPK, UX_DATESAVED, UX_USERNAME)
IF 
    ErrorMsg 2627 THEN DELETE SAVEDPROMOTIONS WHERE IDPK = IDPROMOTIONSPK 
END IF

But I am uncertain where and how to trap errorcodes in this situation and deal with them.

Then I thought to myself (which can be dangerous) ... Why not look up on entry to the UX with something like the following and then we could perhaps set a flag on the UX to set buttons hidden or shown? So I have also tried

dim LookUpCn as sql::Connection
dim args as sql::Arguments
LookUpCn.open("::name::conn")
table = "SavedPromotions"
'I created arguments based on the Username field (aUserName) and PromotionIDFK (aPromotionID) and DateSaved (aDateSaved) in the UX component.
filter = "username=:aUserName AND PromotionIDFK = :aPromotionID"
result = ":aDateSaved"
filter = evaluate_string(filter)
if sql_lookup(LookUpCn,table,filter,result) <> null_value()
	ui_msg_box("Promotion","Already Saved") 'This never pops up!
end if
cn.close()

I seem to have trouble grasping how to use the fields from the UX in the SQL ... I come from a very different background where you could just add those 'screen' variables into the SQL. Alpha confuses me on this ... I am sure I will get it once I am shown the light I am sure if I had it hammered into my little brain how to translate the variables in the UX into the SQL query, I could probably work it out from there. I'm newish to both SQL and Alpha, but getting there (I hope).

Hopefully I have explained this adequately. All assistance would be gratefully received and if clarification is required, please don't hesitate to ask.

Thanks,

Phil

[PhilM1965]

Re: SQL with unbound fields

It strikes me that the info contained in http://www.ajaxvideotutorials.com/V1...operations.swf is close to what I want to do, and use 'Autodecide', but it seems to be a little too constrained to do what I need it to do. Or perhaps someone could shed some light for me on how to configure it, when I don't already have the primary key field information?

Any assistance, gratefully accepted.

Phil

[PhilM1965]

Re: SQL with unbound fields

No bites.

OK, Simple question, hopefully.

Say I want to assign the value of the unbound field 'UserID' to an argument in a function? How do I get at the value of the field within the function and assign it to an argument?

[DaveF]

Re: SQL with unbound fields

You can find examples of how to reference your UX fields on the server-side in the afterDialogValidate event. There are several variations. You can access your unbound fields anytime on the server-side as long as you have access to the “e” object. All of the Alpha server-side events have access to the “e” object and so do Ajax callbacks.

For example, if you create an Ajax callback on a button click event and want to do something with the UserID field, you would use the following variable name to reference it:

request.variables.v.r1.userid

If you want to add the value of your UserID field to an argument list?

args.add("aUserID", request.variables.v.r1.userid)

"aUserID" is the name of the temporary argument. "userid" in "request.variables.v.r1.userid" must be the same as the name you assigned to your control. All Xbasic alpha characters are case insensitive.

[PhilM1965]

Re: SQL with unbound fields

Hi Dave

What I finally ended up with is as follows ... using Firebug, I saw the values I wanted in the e.oldDataSubmitted values, so I used those.

function CheckFav as L (e as p)
dim LookUpConn as sql::Connection
dim args as sql::Arguments
dim rs as sql::ResultSet
dim sqlQuery as c
dim delSQL as c
dim insSQL as c
args.Add("PID", e.oldDataSubmitted.idPromotionsPK)
args.Add("UN", e.oldDataSubmitted.aUserID)
args.Add("sDATE", e.oldDataSubmitted.aDateSaved)
LookUpConn.open("::name::conn")
sqlQuery = "Select count(*) from SavedPromotions where UserID = :UN AND PromotionIDFK = :PID"
delSQL = "DELETE FROM SavedPromotions WHERE PromotionIDFK=:PID AND UserID =:UN"
insSQL = "Insert into SavedPromotions (PromotionIDFK,DateSaved,UserID) VALUES(:PID,:sDATE,:UN)"
sqlQuery = evaluate_string(sqlQuery)
delSQL = evaluate_string(delSQL)
insSQL = evaluate_string(insSQL)
LookUpConn.execute(sqlQuery,args)
rs = LookUpConn.ResultSet
if rs.data(1) > 0 	
	LookUpConn.Execute(delSQL, args)
	LookUpConn.close()
	return .T.
else
	LookUpConn.Execute(insSQL, args)
	LookUpConn.close()
	return .F.
end if
end function

Thanks for pointing me in the right direction and taking the time to respond. I now have the function working as I want