DBeval for unique values

[Marc Venken]

Hello,

Is there a function to fill a array with unique values from a dbf field ?

Ex. STate has : A B C A B B B D

the array should have A,B,C,D

The purpose is in a Xbrowse to filter data with a combo from a
BarGet.

[James Bott]

There is a "UNIQUE" clause for indexes:

INDEX … UNIQUE

That might help. However, It seems to me that you have already established the set of unique values, or are you going to let users enter new values too?

Perhaps you need a separate database for these.

I think we need more information.

[Marc Venken]

James,

Asume the folowing

I will Xbrowse all Customers and many colums end have the getbars on top of Xbrowse.

I can put "Senford" in the col city, hit the filter button and I will have all customers from Senford.

No let say that I don't know the possible city's. Therefore I want to make a Combobox in the Xbrowse with the unique city's.

Your suggestion is right. I could make a temp dbf or index and then fill a array for the combo.

Maybe FW_dbftoarr has a option. I will look into it.

Thanks

[nageswaragunupudi]

For example, we need an array of unique values of the field STATE from customer.dbf

Case-1:
If you already have a Unique Index on STATE.

Code: Select all  Expand view

aVals := {}
SET ORDER TO TAG STATEUNQ
DBGOTOP()
DBEVAL( { || AAdd( aVals, FIELD->STATE } )
 

Case-2:
You have a normal index on STATE ( not unique )

Code: Select all  Expand view

   OrdSetFocus( "STATE" )
   DBGOTOP()
   do while !Eof()
      AADD( aVals, OrdKeyVal() )
      OrdSkipUnique()
   enddo
 

Case-3:
You do not have index on STATE at all. (neither normal nor unique)
One option is to create a temporary index in memory:

Code: Select all  Expand view

   INDEX ON STATE TAG STATEUNQ TO TMP MEMORY ADDITIVE UNIQUE
 

Adopt the logic in Case-1.

Case-4
If we do not want to use indexes.

Code: Select all  Expand view

aVals := {}
   DBGOTOP()
   DBEVAL( { || If( AScan( aVals, FIELD->STATE ) == 0, AAdd( aVals, FIELD->STATE ), nil ) } )
   DBGOTOP()
   ASORT( aVals )
 

[Marc Venken]

Thanks you for the options.

Some new technique's for me...

[ukoenig]

Mr. Rao,

I added the 4 array unique-tests to the tDatabase-samples



This doesn't exist
Is there a replacement for it

Case-2 and 3 :
oCust:OrdSkipUnique()

Code: Select all  Expand view

 
// You have a normal index on LAST ( not unique )

oCust:OrdSetFocus( "CUST1" )
oCust:GoTop()
do while !oCust:Eof()
      AADD( aVals, { oCust:Last, oCust:First } )  
      oCust:OrdSkipUnique() // !!!! not possible
enddo
 

That skips unique records on normal index
changed to :

Code: Select all  Expand view

// You have a normal index on LAST ( not unique )

oCust:OrdSetFocus( "CUST1" )
oCust:GoTop()

cStrTest := oCust:Last + oCust:First
lUnique := .F.

DO WHILE !oCust:Eof()
     IF lUnique = .F.
          AADD( aVals, { oCust:Last, oCust:First } )
     ENDIF
     oCust:Skip(+1)
     // OrdSkipUnique() !!!
     IF cStrTest = oCust:Last + oCust:First
          lUnique := .T.
     ELSE
         lUnique := .F.
         cStrTest := oCust:Last + oCust:First
     ENDIF
ENDDO
 

regards
Uwe