This example uses the CreateRelation method to create a Relation between the Employees TableDef and a new TableDef called Departments. This example also demonstrates how creating a new Relation will also create any necessary Indexes in the foreign table (the DepartmentsEmployees Index in the Employees table).
Sub CreateRelationX()
Dim dbsNorthwind As Database
Dim tdfEmployees As TableDef
Dim tdfNew As TableDef
Dim idxNew As Index
Dim relNew As Relation
Dim idxLoop As Index
Set dbsNorthwind = OpenDatabase("Northwind.mdb")
With dbsNorthwind
' Add new field to Employees table.
Set tdfEmployees = .TableDefs!Employees
tdfEmployees.Fields.Append _
tdfEmployees.CreateField("DeptID", dbInteger, 2)
' Create new Departments table.
Set tdfNew = .CreateTableDef("Departments")
With tdfNew
' Create and append Field objects to Fields
' collection of the new TableDef object.
.Fields.Append .CreateField("DeptID", dbInteger, 2)
.Fields.Append .CreateField("DeptName", dbText, 20)
' Create Index object for Departments table.
Set idxNew = .CreateIndex("DeptIDIndex")
' Create and append Field object to Fields
' collection of the new Index object.
idxNew.Fields.Append idxNew.CreateField("DeptID")
' The index in the primary table must be Unique in
' order to be part of a Relation.
idxNew.Unique = True
.Indexes.Append idxNew
End With
.TableDefs.Append tdfNew
' Create EmployeesDepartments Relation object, using
' the names of the two tables in the relation.
Set relNew = .CreateRelation("EmployeesDepartments", _
tdfNew.Name, tdfEmployees.Name, _
dbRelationUpdateCascade)
' Create Field object for the Fields collection of the
' new Relation object. Set the Name and ForeignName
' properties based on the fields to be used for the
' relation.
relNew.Fields.Append relNew.CreateField("DeptID")
relNew.Fields!DeptID.ForeignName = "DeptID"
.Relations.Append relNew
' Print report.
Debug.Print "Properties of " & relNew.Name & _
" Relation"
Debug.Print " Table = " & relNew.Table
Debug.Print " ForeignTable = " & _
relNew.ForeignTable
Debug.Print "Fields of " & relNew.Name & " Relation"
With relNew.Fields!DeptID
Debug.Print " " & .Name
Debug.Print " Name = " & .Name
Debug.Print " ForeignName = " & .ForeignName
End With
Debug.Print "Indexes in " & tdfEmployees.Name & _
" TableDef"
For Each idxLoop In tdfEmployees.Indexes
Debug.Print " " & idxLoop.Name & _
", Foreign = " & idxLoop.Foreign
Next idxLoop
' Delete new objects because this is a demonstration.
.Relations.Delete relNew.Name
.TableDefs.Delete tdfNew.Name
tdfEmployees.Fields.Delete "DeptID"
.Close
End With
End Sub