Function FieldInfo() | Xbase++

Sets or returns the settings for a field.

FieldInfo( <nFieldPos>, <nDefine>, ;
                     [<xNewSetting>] ) --> xOldValue

<nFieldPos> is a positive integer specifying the ordinal position of the field whose settings are to be accessed within the work area.

For the parameter <nDefine>, a #define constant from the #include file DMLB.CH is used. Constants for <nDefine> begin with the prefix FLD_.

If included, the setting specified with <nDefine> is replaced by the value <xNewSetting>. A replacement is only possible for settings that may be changed.

The return value of FieldInfo() is the value for the field setting specified by <nDefine>. If this is a changeable setting and <xNewSetting> is specified, the function returns the old value.

The function FieldInfo() allows information about individual fields (field variables) in a work area to be accessed. To do this, a file must be open in the work area. If there is not an open file, a runtime error is generated when FieldInfo() is called. A detailed description of the information that can be retrieved using FieldInfo() is found in the chapter The Xbase++ Database Engine in the Xbase++ documentation.

Information about a work area can be retrieved using the function DbInfo().

Determine the structure of a single database field.


// The example shows the UDF FieldStruct() which returns 
// an array containing the structure of a single field. 
// The array structure is the same as a subarray of the 
// DbStruct() array. 

#include "Dmlb.ch" 

************** 
PROCEDURE Main 

   USE Customer 

   ? FieldName( 1 )      // result: CUSTOMERNO 
   ? FieldStruct( 1 )    // result: {CUSTOMERNO, C,      6,      0} 

   USE 
RETURN 

********************************* 
FUNCTION FieldStruct( nFieldPos ) 
RETURN { FieldName( nFieldPos )           , ;  // field name 
         FieldInfo( nFieldPos, FLD_TYPE ) , ;  // data type 
         FieldInfo( nFieldPos, FLD_LEN  ) , ;  // field length 
         FieldInfo( nFieldPos, FLD_DEC  )   }  // decimal places

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Function FieldInfo() Foundation