我有几个具有确切表结构的mdb文件。我必须将主表的主键从autonumber更改为所有这些中的数字，这意味着我必须：
有没有办法从一个文件导出关系并将它们导入到其余文件中？
我确信这可以通过一些宏/ vb代码来完成。有没有人有我可以使用的例子？
感谢。
答案 0 :(得分：12)
不是一个完整的解决方案，但这可能会让你去......
以下函数将打印出所有关系的元数据。将其更改为以您喜欢的任何格式保存到文件（CSV，制表符分隔，XML等）：
Function PrintRelationships()
For Each rel In CurrentDb.Relations
With rel
Debug.Print "Name: " & .Name
Debug.Print "Attributes: " & .Attributes
Debug.Print "Table: " & .Table
Debug.Print "ForeignTable: " & .ForeignTable
Debug.Print "Fields:"
For Each fld In .Fields
Debug.Print "Field: " & fld.Name
Next
End With
Next
End Function
此函数将删除数据库中的所有关系：
Function DropRelationships()
With CurrentDb
For Each rel In .Relations
.Relations.Delete Name:=rel.Name
Next
End With
End Function
此功能将创建一种关系。您将不得不迭代保存的关系数据文件。
Function CreateRelationships()
With CurrentDb
Set rel = .CreateRelation(Name:="[rel.Name]", Table:="[rel.Table]", ForeignTable:="[rel.FireignTable]", Attributes:=[rel.Attributes])
rel.Fields.Append rel.CreateField("[fld.Name for relation]")
rel.Fields("[fld.Name for relation]").ForeignName = "[fld.Name for relation]"
.Relations.Append rel
End With
End Function
由于时间限制而忽略了错误处理和IO（必须让孩子们上床睡觉）。
希望这有帮助。
答案 1 :(得分：1)
在我看来，您可以使用在任何更改之前创建的文件的备份来恢复索引和关系。这是一些笔记。
Sub RunExamples()
Dim strCopyMDB As String
Dim fs As FileSystemObject
Dim blnFound As Boolean
Dim i
' This code is not intended for general users, it is sample code built '
' around the OP '
'You will need a reference to the Microsoft DAO 3.x Object Library '
'This line causes an error, but it will run '
'It is not suitable for anything other than saving a little time '
'when setting up a new database '
Application.References.AddFromFile ("C:\Program Files\Common Files\Microsoft Shared\DAO\dao360.dll")
'You must first create a back-up copy '
Set fs = CreateObject("Scripting.FileSystemObject")
strCopyMDB = CurrentProject.Path & "\c.mdb"
blnFound = fs.FileExists(strCopyMDB)
i = 0
Do While blnFound
strCopyMDB = CurrentProject.Path & "\c" & i & ".mdb"
blnFound = fs.FileExists(strCopyMDB)
Loop
fs.CopyFile CurrentProject.FullName, strCopyMDB
ChangeTables
AddIndexesFromBU strCopyMDB
AddRelationsFromBU strCopyMDB
End Sub
Sub ChangeTables()
Dim db As Database
Dim tdf As DAO.TableDef
Dim rel As DAO.Relation
Dim fld As DAO.Field
Dim ndx As DAO.Index
Dim i
Set db = CurrentDb
'In order to programmatically change an autonumber, '
'it is necessary to delete any relationships that '
'depend on it. '
'When deleting from a collection, it is best '
'to iterate backwards. '
For i = db.Relations.Count - 1 To 0 Step -1
db.Relations.Delete db.Relations(i).Name
Next
'The indexes must also be deleted or the '
'number cannot be changed. '
For Each tdf In db.TableDefs
If Left(tdf.Name, 4) <> "Msys" Then
For i = tdf.Indexes.Count - 1 To 0 Step -1
tdf.Indexes.Delete tdf.Indexes(i).Name
Next
tdf.Indexes.Refresh
For Each fld In tdf.Fields
'If the field is an autonumber, '
'use code supplied by MS to change the type '
If (fld.Attributes And dbAutoIncrField) Then
AlterFieldType tdf.Name, fld.Name, "Long"
End If
Next
End If
Next
End Sub
Sub AddIndexesFromBU(MDBBU)
Dim db As Database
Dim dbBU As Database
Dim tdf As DAO.TableDef
Dim tdfBU As DAO.TableDef
Dim ndx As DAO.Index
Dim ndxBU As DAO.Index
Dim i
Set db = CurrentDb
'This is the back-up made before starting '
Set dbBU = OpenDatabase(MDBBU)
For Each tdfBU In dbBU.TableDefs
'Skip system tables '
If Left(tdfBU.Name, 4) <> "Msys" Then
For i = tdfBU.Indexes.Count - 1 To 0 Step -1
'Get each index from the back-up '
Set ndxBU = tdfBU.Indexes(i)
Set tdf = db.TableDefs(tdfBU.Name)
Set ndx = tdf.CreateIndex(ndxBU.Name)
ndx.Fields = ndxBU.Fields
ndx.IgnoreNulls = ndxBU.IgnoreNulls
ndx.Primary = ndxBU.Primary
ndx.Required = ndxBU.Required
ndx.Unique = ndxBU.Unique
' and add it to the current db '
tdf.Indexes.Append ndx
Next
tdf.Indexes.Refresh
End If
Next
End Sub
Sub AddRelationsFromBU(MDBBU)
Dim db As Database
Dim dbBU As Database
Dim rel As DAO.Relation
Dim fld As DAO.Field
Dim relBU As DAO.Relation
Dim i, j, f
On Error GoTo ErrTrap
Set db = CurrentDb
'The back-up again '
Set dbBU = OpenDatabase(MDBBU)
For i = dbBU.Relations.Count - 1 To 0 Step -1
'Get each relationship from bu '
Set relBU = dbBU.Relations(i)
Debug.Print relBU.Name
Set rel = db.CreateRelation(relBU.Name, relBU.Table, relBU.ForeignTable, relBU.Attributes)
For j = 0 To relBU.Fields.Count - 1
f = relBU.Fields(j).Name
rel.Fields.Append rel.CreateField(f)
rel.Fields(f).ForeignName = relBU.Fields(j).ForeignName
Next
'For some relationships, I am getting error'
'3284 Index already exists, which I will try'
'and track down tomorrow, I hope'
'EDIT: Apparently this is due to Access creating hidden indexes
'and tracking these down would take quite a bit of effort
'more information can be found in this link:
'http://groups.google.ie/group/microsoft.public.access/browse_thread/thread/ca58ce291bdc62df?hl=en&ie=UTF-8&q=create+relation+3284+Index+already+exists
'It is an occasional problem, so I've added an error trap
'Add the relationship to the current db'
db.Relations.Append rel
Next
ExitHere:
Exit Sub
ErrTrap:
If Err.Number = 3284 Then
Debug.Print relBU.Name, relBU.Table, relBU.ForeignTable, relBU.Attributes
Resume Next
Else
'this is not a user sub, so may as well ... '
Stop
End If
End Sub
Sub AlterFieldType(TblName As String, FieldName As String, _
NewDataType As String)
'http://support.microsoft.com/kb/128016'
Dim db As Database
Dim qdf As QueryDef
Set db = CurrentDb()
' Create a dummy QueryDef object.'
Set qdf = db.CreateQueryDef("", "Select * from PROD1")
' Add a temporary field to the table.'
qdf.SQL = "ALTER TABLE [" & TblName & "] ADD COLUMN AlterTempField " & NewDataType
qdf.Execute
' Copy the data from old field into the new field.'
qdf.SQL = "UPDATE DISTINCTROW [" & TblName _
& "] SET AlterTempField = [" & FieldName & "]"
qdf.Execute
' Delete the old field.'
qdf.SQL = "ALTER TABLE [" & TblName & "] DROP COLUMN [" _
& FieldName & "]"
qdf.Execute
' Rename the temporary field to the old field's name.'
db.TableDefs("[" & TblName & "]").Fields("AlterTempField").Name = FieldName
End Sub
答案 2 :(得分：1)
根据@Patrick Cuff的回答，我创建了一对脚本：一个导出到xml，另一个读取这个xml并将其解析到数据库中
'supply the Access Application object into this function and path to file to which the output should be written
Function ExportRelationships(oApplication, sExportpath)
Dim relDoc, myObj
Set relDoc = CreateObject("Microsoft.XMLDOM")
relDoc.appendChild relDoc.createElement("Relations") 'create root xml element
'loop though all the relations
For Each myObj In oApplication.CurrentDb.Relations
If Not Left(myObj.Name, 4) = "MSys" Then 'exclude system relations
Dim relName, relAttrib, relTable, relFoTable, fld
relDoc.childNodes(0).appendChild relDoc.createElement("Relation")
Set relName = relDoc.createElement("Name")
relName.Text = myObj.Name
relDoc.childNodes(0).lastChild.appendChild relName
Set relAttrib = relDoc.createElement("Attributes")
relAttrib.Text = myObj.Attributes
relDoc.childNodes(0).lastChild.appendChild relAttrib
Set relTable = relDoc.createElement("Table")
relTable.Text = myObj.Table
relDoc.childNodes(0).lastChild.appendChild relTable
Set relFoTable = relDoc.createElement("ForeignTable")
relFoTable.Text = myObj.ForeignTable
relDoc.childNodes(0).lastChild.appendChild relFoTable
'in case the relationship works with more fields
For Each fld In myObj.Fields
Dim lf, ff
relDoc.childNodes(0).lastChild.appendChild relDoc.createElement("Field")
Set lf = relDoc.createElement("Name")
lf.Text = fld.Name
relDoc.childNodes(0).lastChild.lastChild.appendChild lf
Set ff = relDoc.createElement("ForeignName")
ff.Text = fld.ForeignName
relDoc.childNodes(0).lastChild.lastChild.appendChild ff
Next
End If
Next
relDoc.insertBefore relDoc.createProcessingInstruction("xml","version='1.0'"), relDoc.childNodes(0)
relDoc.Save sExportpath
End Function
'supply the Access Application object into this function and path to file from which the input should be read
Function ImportRelationships(oApplication, sImportpath)
Dim relDoc, myObj
Set relDoc = CreateObject("Microsoft.XMLDOM")
relDoc.Load(sImportpath)
Dim xmlRel, xmlField, accessRel, relTable, relName, relFTable, relAttr, i
'loop through every Relation node inside .xml file
For Each xmlRel in relDoc.selectNodes("/Relations/Relation")
relName = xmlRel.selectSingleNode("Name").Text
relTable = xmlRel.selectSingleNode("Table").Text
relFTable = xmlRel.selectSingleNode("ForeignTable").Text
relAttr = xmlRel.selectSingleNode("Attributes").Text
'remove any possible conflicting relations or indexes
On Error Resume next
oApplication.CurrentDb.Relations.Delete (relName)
oApplication.CurrentDb.TableDefs(relTable).Indexes.Delete(relName)
oApplication.CurrentDb.TableDefs(relFTable).Indexes.Delete(relName)
On Error Goto 0
'create the relationship object
Set accessRel = oApplication.CurrentDb.CreateRelation(relName, relTable, relFTable, relAttr)
'in case the relationship works with more fields
For Each xmlField In xmlRel.selectNodes("Field")
accessRel.Fields.Append accessRel.CreateField(xmlField.selectSingleNode("Name").Text)
accessRel.Fields(xmlField.selectSingleNode("Name").Text).ForeignName = xmlField.selectSingleNode("ForeignName").Text
Next
'and finally append the newly created relationship to the database
oApplication.CurrentDb.Relations.Append accessRel
Next
End Function
只是为了澄清预期将传递给 oApplication 参数
的内容Set oApplication = CreateObject("Access.Application")
oApplication.NewCurrentDatabase path 'new database
oApplication.OpenCurrentDatabase path 'existing database
如果您从VBA而不是VBScript运行此操作，则可以在使用 oApplication 的代码中的任何位置删除参数和常规 Application 对象。
我开始研究这段代码，因为我需要在非常复杂的MsAccess项目上实现版本控制。 This post让我感动，对于如何导出/导入MsAccess项目的其他部分也有一些很好的建议。
答案 3 :(得分：0)
感谢您的代码段。 为了摆脱你的3284错误，我改变了一些事情。 如果从样本mdb中复制所有索引，然后尝试放置关系，则会抛出异常，因为当您放置关系时，它会预期不存在关系映射的idex，它会放置自己的索引。 我遵循的步骤是（假设target.mdb和source.mdb）：
target.mdb通过调用ChangeTables AddIndexesFromBU source.mdb并使用条件ndxBU.Unique则tdf.Indexes.Append ndx结束如果这将只输出唯一索引source.mdb并填写所有关系ndxBU.Unique然后我还在AddIndexesFromBU中添加了与AddRelationsFromBU相同的错误陷阱，并为if if else
继续下一步这对我有用。