Determinar si un campo es AutoIncremental

Determinar si es un campo específico es un campo AutoIncremental, es un poco molesto. Esa información está solamente disponible comprobando la 17° o 18° columna de la matriz creada por AFIELDS() en la fila del campo.

La rutina X8IsAutoInc.PRG de este artículo hace que esa información sea fácil de consultar.

* 
*  X8IsAutoInc.PRG
*
*  RETURNs a logical value indicating whether the
*  passed field is an AutoInc field.
*
*  Author:  Drew Speedie  
*
*  lParameters
*  tcFieldName (R)  FieldName or Alias.FieldName
*                     to be checked to see if it
*                     is an AutoInc field.
*      tcAlias (O)  If tcFieldName is passed as
*                     Alias.FieldName, this parameter
*                     is ignored.
*                   If tcFieldName is passed as 
*                     just a FieldName, this parameter
*                     is REQUIRED, specifying the ALIAS()
*                     whose tcFieldName is to be
*                     checked to see if it is an AutoInc
*                     field.
*
*  If tcFieldName is in a REMOTE VIEW, this routine
*    RETURNS .F.
*  If tcFieldName is in a LOCAL VIEW, this routine 
*    RETURNS a logical value indicating whether tcFieldName
*    in its base table is an AutoInc field.
*
*  The Alias specified in tcFieldName/tcAlias must be USED(),
*  if the Alias is a local view, its base table must
*  also be USED().
*
LPARAMETERS tcFieldName, tcAlias

IF VERSION(5) < 800
  RETURN .f.
ENDIF

IF NOT VARTYPE(tcFieldName) = "C" ;
     OR EMPTY(tcFieldName) 
  ASSERT .f. MESSAGE "tcFieldName is required"
  RETURN .NULL.
ENDIF

LOCAL lcAlias, lcFieldName
lcFieldName = UPPER(ALLTRIM(tcFieldName))
IF OCCURS(".",lcFieldName) = 1
  lcAlias = JUSTSTEM(lcFieldName)
  lcFieldName = JUSTEXT(lcFieldName)
 ELSE
  IF VARTYPE(tcAlias) = "C" AND NOT EMPTY(tcAlias) 
    lcAlias = UPPER(ALLTRIM(tcAlias))
   ELSE
    ASSERT .f. MESSAGE "tcAlias is required when po does not include the Alias"
    RETURN .NULL.
  ENDIF
ENDIF       

IF CURSORGETPROP("SourceType",lcAlias) = 2
  *
  *  remote view
  *
  RETURN .f.
ENDIF

LOCAL laFields[1], xx, llAutoInc, llView, lnSelect
llAutoInc = .f.

lnSelect = SELECT(0)
SELECT (lcAlias)

llView = CURSORGETPROP("SourceType",lcAlias) = 1
IF llView
  lcAlias = X8BTABLE(lcAlias+"."+lcFieldName,CURSORGETPROP("Database",lcAlias))
  SELECT (lcAlias)
ENDIF

AFIELDS(laFields)
xx = ASCAN(laFields,lcFieldName,1,-1,1,15)
IF xx > 0
  llAutoInc = laFields[xx,17] > 0
ENDIF

SELECT (lnSelect)

RETURN llAutoInc

VFP Tips & Tricks - Drew Speedie