Sunday, 24 June 2012

Ex14: VBA - Index on field using DAO

Indicate if there is a single-field index using DAO in VBA

Option Compare Database
Option Explicit

'Constants for examining how a field is indexed.
Private Const intcIndexNone As Integer = 0
Private Const intcIndexGeneral As Integer = 1
Private Const intcIndexUnique As Integer = 3
Private Const intcIndexPrimary As Integer = 7

Private Function IndexOnField(tdf As DAO.TableDef, fld As DAO.Field) _
As Integer
    'Purpose:   Indicate if there is a single-field index _
    '               on this field in this table.
    'Return:    The constant indicating the strongest type.
    Dim ind As DAO.Index
    Dim intReturn As Integer
    intReturn = intcIndexNone
    For Each ind In tdf.Indexes
        If ind.Fields.Count = 1 Then
            If ind.Fields(0).Name = fld.Name Then
                If ind.Primary Then
                    intReturn = (intReturn Or intcIndexPrimary)
                ElseIf ind.Unique Then
                    intReturn = (intReturn Or intcIndexUnique)
                    intReturn = (intReturn Or intcIndexGeneral)
                End If
            End If
        End If
    'Clean up
    Set ind = Nothing
    IndexOnField = intReturn
End Function

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