索引集合 (DAO)

适用于：Access 2013、Office 2013

Indexes 对象包含 TableDef 对象的所有存储的 Index 对象（仅适用于 Microsoft Access 工作区）。

备注

访问表类型的 Recordset 对象时，使用对象的 Index 属性来指定记录的顺序。 将此属性设置为 Recordset 对象基础的 TableDef 对象的 Indexes 集合中现有 Index 对象的 Name 属性设置。

注意

[!注释] 仅当包含 Indexes 集合的 TableDef 对象的 Updatable 属性设置为 True 时，才能对该集合使用 Append 或 Delete 方法。

创建新的 Index 对象之后，应使用 Append 方法将该对象添加到 TableDef 对象的 Indexes 集合中。

重要

[!重要信息] 确保数据符合新索引的属性。 如果索引需要唯一值，请确保现有数据记录中没有重复值。 如果存在重复值，Microsoft Access 数据库引擎将无法创建索引；当您尝试对新索引使用 Append 方法时，会生成可捕获的错误。

示例

以下示例创建一个新的 Index 对象，并将该对象追加到 Employees TableDef 的 Indexes 集合，然后枚举 TableDef 的 Indexes 集合。 最后，该示例枚举 Recordset，方法是首先使用主 Index，然后使用新的 Index。 若要使该过程正常运行，需要使用 IndexOutput 过程。

    Sub IndexObjectX() 
     
     Dim dbsNorthwind As Database 
     Dim tdfEmployees As TableDef 
     Dim idxNew As Index 
     Dim idxLoop As Index 
     Dim rstEmployees As Recordset 
     
     Set dbsNorthwind = OpenDatabase("Northwind.mdb") 
     Set tdfEmployees = dbsNorthwind!Employees 
     
     With tdfEmployees 
     ' Create new index, create and append Field 
     ' objects to its Fields collection. 
     Set idxNew = .CreateIndex("NewIndex") 
     
     With idxNew 
     .Fields.Append .CreateField("Country") 
     .Fields.Append .CreateField("LastName") 
     .Fields.Append .CreateField("FirstName") 
     End With 
     
     ' Add new Index object to the Indexes collection 
     ' of the Employees table collection. 
     .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 
     Next idxLoop 
     
     Set rstEmployees = _ 
     dbsNorthwind.OpenRecordset("Employees") 
     
     ' Print report using old and new indexes. 
     IndexOutput rstEmployees, "PrimaryKey" 
     IndexOutput rstEmployees, idxNew.Name 
     rstEmployees.Close 
     
     ' Delete new Index because this is a 
     ' demonstration. 
     .Indexes.Delete idxNew.Name 
     End With 
     
     dbsNorthwind.Close 
     
    End Sub 
     
    Sub IndexOutput(rstTemp As Recordset, _ 
     strIndex As String) 
     ' Report function for FieldX. 
     
     With rstTemp 
     ' Set the index. 
     .Index = strIndex 
     .MoveFirst 
     Debug.Print "Recordset = " & .Name & _ 
     ", Index = " & .Index 
     Debug.Print " EmployeeID - Country - Name" 
     
     ' Enumerate the recordset using the specified 
     ' index. 
     Do While Not .EOF 
     Debug.Print " " & !EmployeeID & " - " & _ 
     !Country & " - " & !LastName & ", " & !FirstName 
     .MoveNext 
     Loop 
     
     End With 
     
    End Sub 

以下示例使用 CreateIndex 方法创建两个新的 Index 对象，然后将它们追加到 Employees TableDef 对象的 Indexes 集合。 然后，该示例枚举 TableDef 对象的 Indexes 集合、新 Index 对象的 Fields 集合，以及新 Index 对象的 Properties 集合。 若要使该过程正常运行，需要使用 CreateIndexOutput 函数。

    Sub CreateIndexX() 
     
     Dim dbsNorthwind As Database 
     Dim tdfEmployees As TableDef 
     Dim idxCountry As Index 
     Dim idxFirstName As Index 
     Dim idxLoop As Index 
     
     Set dbsNorthwind = OpenDatabase("Northwind.mdb") 
     Set tdfEmployees = dbsNorthwind!Employees 
     
     With tdfEmployees 
     ' Create first Index object, create and append Field 
     ' objects to the Index object, and then append the 
     ' Index object to the Indexes collection of the 
     ' TableDef. 
     Set idxCountry = .CreateIndex("CountryIndex") 
     With idxCountry 
     .Fields.Append .CreateField("Country") 
     .Fields.Append .CreateField("LastName") 
     .Fields.Append .CreateField("FirstName") 
     End With 
     .Indexes.Append idxCountry 
     
     ' Create second Index object, create and append Field 
     ' objects to the Index object, and then append the 
     ' Index object to the Indexes collection of the 
     ' TableDef. 
     Set idxFirstName = .CreateIndex 
     With idxFirstName 
     .Name = "FirstNameIndex" 
     .Fields.Append .CreateField("FirstName") 
     .Fields.Append .CreateField("LastName") 
     End With 
     .Indexes.Append idxFirstName 
     
     ' Refresh collection so that you can access new Index 
     ' objects. 
     .Indexes.Refresh 
     
     Debug.Print .Indexes.Count & " Indexes in " & _ 
     .Name & " TableDef" 
     
     ' Enumerate Indexes collection. 
     For Each idxLoop In .Indexes 
     Debug.Print " " & idxLoop.Name 
     Next idxLoop 
     
     ' Print report. 
     CreateIndexOutput idxCountry 
     CreateIndexOutput idxFirstName 
     
     ' Delete new Index objects because this is a 
     ' demonstration. 
     .Indexes.Delete idxCountry.Name 
     .Indexes.Delete idxFirstName.Name 
     End With 
     
     dbsNorthwind.Close 
     
    End Sub 
     
    Function CreateIndexOutput(idxTemp As Index) 
     
     Dim fldLoop As Field 
     Dim prpLoop As Property 
     
     With idxTemp 
     ' Enumerate Fields collection of Index object. 
     Debug.Print "Fields in " & .Name 
     For Each fldLoop In .Fields 
     Debug.Print " " & fldLoop.Name 
     Next fldLoop 
     
     ' Enumerate Properties collection of Index object. 
     Debug.Print "Properties of " & .Name 
     For Each prpLoop In .Properties 
     Debug.Print " " & prpLoop.Name & " - " & _ 
     IIf(prpLoop = "", "[empty]", prpLoop) 
     Next prpLoop 
     End With 
     
    End Function