Nadya

>>We had indexseek before, but it didn't work.
>>Here is how our classes work: If you hit Add, it uses APPEND BLANK command, so the empty record is already added in the database. Now, on the field, which requires validation, we should check for uniqueness, and if it fails, user has option to revert.

And the problems you're running into now illustrate why its a bad idea to do an APPEND BLANK before you've got the data to put into the new recod.

>As a further step, you might consider writing a primary key validation class as part of a business tier. Keep the business code out of the interface layer and all that.
>>That's a good idea, but I'm not sure, how to implement it. Can you show an example?



Damn girl... not asking for much!

OK. The enclosed code is for illustration purposes only. I'm expressly saying that it will not work as supplied.
The idea behind a business tier is to make a hard division between the business-rule code and the interface code.
If you decide to go with another COM compatible language for the interface (i.e. VB) your business code doesn't have to be rewritten.
Even if you stay with VFP, a major change in the interface paradigm has no impact on the business-tier code.

Also, I wasn't aware that you were working with a framework. Multi-tier code IS a type of framework and
your current framework doesn't appear to support multiple tiers. What you may want to do is start small.
Write a class for the AllFunctions table that supports any business rules you need applied to that table.

BTW, for all you eagle eyes out there, don't bust my chops about small stuff. If I were writing this
for a real application, there's a number of things in this example I wouldn't do either.
The intent is to show the type of functionality typically found in a business tier and the
kind of code used to enforce encapsulation.

Regards,
Thom C.

**************************************************
*-- Class:        allfct_busytier (d:\playvfp\arbwork.vcx)
*-- ParentClass:  custom
*-- BaseClass:    custom
*-- Time Stamp:   06/14/01 01:49:10 PM
*
DEFINE CLASS allfct_busytier AS custom

	*** properties that express the table and important indexes
	pctable = "AllFunctions"
	pctag = "Fun_Key"
	*-- Index tag for the primekey.
	pc_pkeytag = "AllF_PKey"
	
	*** buffer properties for the field values
	*-- Old value of AllFunctions.FunName
	pcfunname_old = ""
	*-- New value of Allfunctions.FunName
	pcfunname_new = ""
	*-- Old value of some numeric field in AllFunctions
	pnallfun_1_old = 0
	*-- New value of some numeric field in AllFunctions
	pnallfun_1_new = 0
	*-- Old value of some date field in AllFunctions
	pdallfun_1_old = ""
	*-- New value of some date field in AllFunctions
	pdallfun_1_new = ""
	*-- Value of the AllFunctions primary key.
	pn_allf_pkey = 0
	
	Name = "allfct_busytier"


	*-- Find a given AllFunctions record and load THIS's properties.
	PROCEDURE load_funct
		LPARAMETER tnKeyVal
		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF

			IF INDEXSEEK((m.tnKeyVal), .F., (.pcTable), (.pc_PKeyTag))
				.pnAllF_PKey = AllFunctions.PrimeKey
				.pcFunName_Old = AllFunctions.FunName
				.pc_pnAllFun_1_Old = AllFunctions.NumbField
				.pd_pnAllFun_1_Old = AllFunctions.DateField
			ENDIF
		ENDWITH
	ENDPROC


	*-- Test for possible duplication of the primary key.
	PROCEDURE fun_uniq
		LPARAMETER tcKeyVal

		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF

			m.lRetVal = INDEXSEEK(m.tcKey, .F., (.pcTable), (.pcTag))
		ENDWITH

		RETURN(m.lRetVal)
	ENDPROC


	*-- Add a new function
	PROCEDURE add_newfunct
		LOCAL ARRAY laInsVals[4]

		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF

			IF .Fun_Uniq(.pcFunName_New)
				laInsVals[2] = .pcFunName_New
				laInsVals[3] = IIF(EMPTY(.pnAllFun_1_New), .pc_pnAllFun_1_Old, .pcAllFun_1_New)
				laInsVals[4] = IIF(EMPTY(.pdAllFun_1_New), .pd_pnAllFun_1_Old, .pdAllFun_1_New)
				laInsVals[1] = .New_PKey()

				INSERT INTO AllFunctions ;
					FROM ARRAY laInsVals
			ENDIF
		ENDWITH
	ENDPROC


	*-- Apply changes to a record in AllFunctions
	PROCEDURE upd_funct
		LOCAL ARRAY laUpdVals[4]

		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF

			IF INDEXSEEK((.pnAllF_PKey), .T., (.pcTable), (.pc_PKeyTag))
				laUpdVals[1] = .pnAllF_PKey
				laUpdVals[2] = IIF(EMPTY(.pcFunName_New), .pcFunName_Old, .pcFunName_New)
				laUpdVals[3] = IIF(EMPTY(.pnAllFun_1_New), .pn_pnAllFun_1_Old, .pnAllFun_1_New)
				laUpdVals[4] = IIF(EMPTY(.pdAllFun_1_New), .pd_AllFun_1_Old, .pdAllFun_1_New)

				SELECT (.pcTable)
				GATHER FROM laUpdVals
			ENDIF
		ENDWITH
	ENDPROC


	*-- Delete a function.
	PROCEDURE del_funct
		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF

			IF INDEXSEEK(.pn_AllF_PKey, .T., (.pcTable), (.pc_Pkeytag))
				DELETE IN (.pcTable)
			ENDIF
		ENDWITH
	ENDPROC


	*-- Validate the date field value.
	PROCEDURE valid_pdfunct
		LPARAMETER tdValue

		[Code to verify the validity of m.tdValue]

		IF m.tdValue = Valid
			THIS.pd_AllFun_1_New = m.tdValue
		ENDIF
	ENDPROC


	*-- Validate the numeric field value.
	PROCEDURE valid_pnfunct
		LPARAMETER tnValue

		[Code to verify the validity of m.tnValue]

		IF m.tnValue = Valid
			THIS.pn_AllFun_1_New = m.tnValue
		ENDIF
	ENDPROC


	*-- Test for a unique prime key.
	PROCEDURE uniq_pkey
		LOCAL lRetVal
		WITH THIS
			m.lRetVal = INDEXSEEK((.pnAllF_PKey), .F., (.pcTable), (.pc_PKeyTag))
		ENDWITH
		RETURN(m.lRetVal)
	ENDPROC


	*-- Get the next primekey.
	PROCEDURE new_pkey
		LOCAL lnRetVal

		WITH THIS
			IF NOT USED(.pcTable)
				USE (.pcTable) IN 0
			ENDIF
			SELECT (.pcTable)
			SET ORDER TO (.pc_PKeyTag)

			GO BOTT

			m.lnRetVal = AllFunctions.Primekey + 1
		ENDWITH

		RETURN(m.lnRetVal)
	ENDPROC


ENDDEFINE
*
*-- EndDefine: allfct_busytier
**************************************************