ORDKEY()
 Return the key expression of an order
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 Syntax

     ORDKEY(<cOrderName> | <nOrder>
        [, <cOrderBagName>]) --> cExpKey

 Arguments

     <cOrderName> is the name of an order, a logical ordering of a
     database.

     <nOrder> is an integer that identifies the position in the order
     list of the target order whose cExpKey is sought.

     <cOrderBagName> is the name of a disk file containing one or more
     orders.  You may specify <cOrderBagName> as the file name with or
     without the path name or appropriate extension.  If you do not include
     the extension as part of <cOrderBagName>, CA-Clipper uses the default
     extension of the current RDD.

 Returns

     Returns a character string, cExpKey.

 Description

     ORDKEY() is an order management function that returns a character
     expression, cExpKey, that represents the key expression of the specified
     order.

     You may specify the order by name or with a number that represents its
     position in the order list.  Using the order name is the preferred
     method.

     The active RDD determines the order capacity of an order bag.  The
     default DBFNTX and the DBFNDX drivers only support single-order bags,
     while other RDDs may support multiple-order bags (e.g., the DBFCDX and
     DBFMDX drivers).

     Note: ORDKEY(0) works as ORDKEY(INDEXORD()).

 Examples

     .  This example retrieves the index expression from an order:

        USE Customer NEW
        INDEX ON  Customer->Acct   ;
           TO  Customer      ;
           FOR Customer->Acct > "AZZZZZ"

        ORDKEY("Customer")      // Returns: Customer->Acct