Template

Function

Name

__dbStructFilter()

Category

API

Subcategory

Database

Oneliner

Filter a database structure array

Syntax

      __dbStructFilter( <aStruct>,  [<aFieldList>] ) --> aStructFiltered

Arguments

<aStruct> is a multidimensional array with database fields structure, which is usually the output from dbStruct(), where each array element has the following structure:

       Position   Description    dbstruct.ch
       --------   -----------    -----------
       1          cFieldName     DBS_NAME
       2          cFieldType     DBS_TYPE
       3          nFieldLength   DBS_LEN
       4          nDecimals      DBS_DEC

<aFieldList> is an array where each element is a field name. Names could be specified as uppercase or lowercase.

Returns

__dbStructFilter() return a new multidimensional array where each element is in the same structure as the original <aStruct>, but the array is built according to the list of fields in <aFieldList>. If <aFieldList> is empty, __dbStructFilter() return reference to the original <aStruct> array.

Description

__dbStructFilter() can be use to create a sub-set of a database structure, based on a given field list.

Note that field names in <aStruct> MUST be specified in uppercase or else no match would be found.

SET EXACT has no effect on the return value.

Examples

      LOCAL aStruct,  aList,  aRet
      aStruct := { ;
         { "CODE",   "N",   4,  0 },  ;
         { "NAME",   "C",  10,  0 },  ;
         { "PHONE",  "C",  13,  0 },  ;
         { "IQ",     "N",   3,  0 } }
      aList := { "IQ",  "NAME" }
      aRet := __dbStructFilter( aStruct,  aList )
                        // { { "IQ",  "N",  3,  0 },  { "NAME",  "C",  10,  0 } }

      aRet := __dbStructFilter( aStruct,  {} )
      ? aRet == aStruct // .T.

      aList := { "iq",  "NOTEXIST" }
      aRet := __dbStructFilter( aStruct,  aList )
                        // { { "IQ",  "N",  3,  0 } }

      aList := { "NOTEXIST" }
      aRet := __dbStructFilter( aStruct,  aList )   // {}

      // Create a new file that contain part of the original structure
      LOCAL aStruct,  aList,  aRet
      USE TEST
      aStruct := dbStruct()
      aList := { "NAME" }
      dbCreate( "onlyname.dbf",  __dbStructFilter( aStruct,  aList ) )

Compliance

__dbStructFilter() is a Harbour extension. CA-Cl*pper has an internal undocumented function named __FLedit() that does exactly the same thing. The new name gives a better description of what this  function does.

Platforms

All

Files

Header file is dbstruct.ch
Library is rdd

Seealso

dbCreate(), dbStruct(), __dbCopyStruct(), __FLedit()*