update cAlias set ttt = ... 
   where ttt= 0 

create cursor tt (id i autoinc, cvalue c( 10 ), uuu i null)
local i
for i= 1  to  100 
	insert into tt (cvalue) values (ltrim(str(i)))
endfor

local loMyCad
loMyCad = createobject('mycad')
with loMyCad
	.SelectCmdSet('1=1')
	select mycursor
	update mycursor set cvalue=cvalue, ;
	                    uuu=null
	if tableupdate(.t.,.t.,"mycursor")
		select * from tt
	else
		local lArr[ 1 ]
		aerror(lArr)
		messagebox('не шмогла tableupdate  '+lArr[ 2 ])
	endif
endwith




DEFINE CLASS mycad AS CursorAdapter

	BufferModeOverride =  5 
	DataSourceType = "Native"
	WhereType =  4 
	ConflictCheckType =  1 
	Alias = "mycursor"
	KeyFieldList = "Id"
	Tables = "tt"
	Name = "mycad"
	UpdatableFieldList = "cvalue, uuu"
	UpdateNameList = "Id tt.Id, cvalue tt.cvalue, uuu tt.uuu"
	ConversionFunc = "uuu checkUUU"
	
	procedure SelectCmdSet
		lparameters tcWhere
		text to this.SelectCmd noshow textmerge pretext  15 
			select *
				from <<this.Tables>>
					where <<tcWhere>>
		endtext
		if this.cursorfill()
			return .t.
		else
			messagebox('не шмогла cursorfill')
		endif
enddefine

procedure checkUUU
	lparameters ttt
	return id+ 10 
endproc