Unique Property Example

This example sets the Unique property of a new Index object to True, and appends the Index to the Indexes collection of the Employees table. It then enumerates the Indexes collection of the TableDef and the Properties collection of each Index. The new Index will only allow one record with a particular combination of Country, LastName, and FirstName in the TableDef.

Sub UniqueX()

   Dim dbsNorthwind As Database
   Dim tdfEmployees As TableDef
   Dim idxNew As Index
   Dim idxLoop As Index
   Dim prpLoop As Property

   Set dbsNorthwind = OpenDatabase("Northwind.mdb")
   Set tdfEmployees = dbsNorthwind!Employees

   With tdfEmployees
      ' Create and append new Index object to the Indexes 
      ' collection of the Employees table.
      Set idxNew = .CreateIndex("NewIndex")

      With idxNew
         .Fields.Append .CreateField("Country")
         .Fields.Append .CreateField("LastName")
         .Fields.Append .CreateField("FirstName")
         .Unique = True
      End With

      .Indexes.Append idxNew
      .Indexes.Refresh

      Debug.Print .Indexes.Count & " Indexes in " & _
         .Name & " TableDef"

      ' Enumerate Indexes collection of Employees table.
      For Each idxLoop In .Indexes
         Debug.Print "  " & idxLoop.Name

         ' Enumerate Properties collection of each Index 
         ' object.
         For Each prpLoop In idxLoop.Properties
            Debug.Print "    " & prpLoop.Name & _
               " = " & IIf(prpLoop = "", "[empty]", prpLoop)
         Next prpLoop

      Next idxLoop

      ' Delete new Index because this is a demonstration.
      .Indexes.Delete idxNew.Name
   End With

   dbsNorthwind.Close

End Sub