This guide demonstrates how to import an XML file created in diagrams.net (formerly draw.io) and extract the necessary properties to construct an Entity Relationship Diagram (ERD). The process focuses on identifying and utilizing specific data embedded within the XML structure to generate accurate and meaningful diagram elements.
To begin, a new diagram was created using diagrams.net:
Then, in this diagram, we have added specific data to the shapes we used in order to identify these objects:
Even though the relationships are linked to the entities, we have added Source & Target properties since the object dropped on the diagram can be linked to many different connection points belonging to various shapes (entity, attribute, PK, FK, etc.).
Finally, we exported our diagram as XML (no compression, current page):
The XML file is too verbose to be nicely shared as text below. You can download it from here.
Here is the script of the macro which can use this XML file:
'#Language "WWB-COM"
''MACRO TITLE: wImportDrawIO
' MACRO VERSION: 1.1
'
' This macro imports Entities Attributes and relationships from a draw.io XML file
'with custom properties
'
' Known limitations:
'- Specific data are required to import the objects
'- Only the first page is imported
'- Compressed XML format is not supported
'
' Blog post: https://blog.idera.com/database-tools/er-studio-data-architect/macros-import-objects-from-a-diagrams-net-xml-file/
'
'-----------------------------------------------------------------------------------
Option Explicit
Const TITLE$ = "wImportDrawIO"
Dim MyModel As Model
Sub Main
Debug.Clear
Begin Dialog UserDialog 720,105,TITLE,.DlgFunc ' %GRID:10,7,1,1
Text 10,21,120,14,"File Path:",.txtFile,1
TextBox 150,21,450,21,.edFileName
PushButton 610,21,90,21,"Select File",.btnSelectFile
PushButton 260,70,90,21,"Import",.btnImport
CancelButton 380,70,90,21,.btnExit
End Dialog
Dim dlg As UserDialog
If Dialog(dlg) = 0 Then Exit Sub
End Sub
Private Sub DoImport(xmlFilename$)
#Region "Variables"
Dim diag As Diagram
Dim MySubModel As SubModel
Dim MyEntity As Entity
Dim MyEntityDisplay As EntityDisplay
Dim MyAttribute As AttributeObj
Dim MyRelationship As Relationship
Dim MyShape As Shape
Dim MyShapeDisplay As ShapeDisplay
Dim xml$
Dim cptEntities%, cptAttributes%, cptRelationships%, cptShapes%
Dim objStream
Dim oXml As MSXML2.DOMDocument60
Dim allItems, oneItem, oneNode As IXMLDOMNode
Dim myProject$, wentity$, wtable$, wid$, wx%, wy%, ww%, wh%
Dim wattribute$, wcolumn$, wdatatype$, wnull$, wpk As Boolean
Dim wname$, wsource$, wtarget$, wrolename$, wstyle$
Dim datatype$, datawidth%, nPos%, s$, nSepPos%, datascale%
Dim StartTime!
#End Region
StartTime = Timer
On Error GoTo Error_detected
' Disable Tree updates: it doesn't work on the DD treeview
DiagramManager.EnableScreenUpdateEx(False, False)
Set diag = DiagramManager.NewDiagram
#Region "XML"
' Load XML from UTF-8 file
Set objStream = CreateObject("ADODB.Stream")
objStream.CharSet = "utf-8"
objStream.Open
objStream.LoadFromFile(xmlFilename)
xml = objStream.ReadText()
objStream.Close
Set objStream = Nothing
' Parse XML
Set oXml = New MSXML2.DOMDocument60
If oXml.loadXML xml Then
Debug.Print "XML loaded"
oXml.async = False
oXml.setProperty "SelectionLanguage", "XPath"
Set allItems = oXml.selectNodes("//mxfile")
#End Region
If allItems.length = 0 Then
MsgBox "Root node not found!", vbExclamation, TITLE
DiagramManager.EnableScreenUpdateEx(True, True)
Exit Sub
Else
Set oneItem = oXml.selectSingleNode("mxfile/diagram")
If oneItem Is Nothing Then
DiagramManager.EnableScreenUpdateEx(True, True)
Exit Sub
Else
' Get the Page name
myProject = GetAttributeValue(oneItem, "name")
diag.ProjectName = myProject
diag.CopyrightYear = "" & Year(Now)
End If
End If
#Region "object"
' Search specific nodes
Set allItems = oneItem.selectNodes("mxGraphModel/root/object")
If allItems.length = 0 Then
Debug.Print "Unknown path"
MsgBox "object not found!", vbExclamation, TITLE
Else
Const UNKNOWN$ = "Unknown"
Set MyModel = diag.ActiveModel
Set MySubModel = MyModel.ActiveSubModel
' Name compartments are displayed
MySubModel.ShowEntityNameCompartment = True
MySubModel.PrimaryKeyFont.Bold = True
' Initialize counters
cptEntities = 0
cptAttributes = 0
cptRelationships = 0
cptShapes = 0
' Loop all matching nodes
For Each oneItem In allItems
' Check if the current XML node has an attribute "TableName"
If GetAttributeValue(oneItem, "TableName") <> "" Then
' ENTITY
wentity = GetAttributeValue(oneItem, "label")
wtable = GetAttributeValue(oneItem, "TableName")
wid = GetAttributeValue(oneItem, "id")
' Required properties are available
If wentity <> "" And wtable <> "" Then
Set oneNode = oneItem.selectSingleNode("mxCell").selectSingleNode("mxGeometry")
If Not oneNode Is Nothing Then
wx = CInt(GetAttributeValue(oneNode, "x"))
wy = CInt(GetAttributeValue(oneNode, "y"))
ww = CInt(GetAttributeValue(oneNode, "width"))
wh = CInt(GetAttributeValue(oneNode, "height"))
Else
wx = 0
wy = 0
ww = 0
wh = 0
End If
' Create the Entity
Set MyEntity = MyModel.Entities.AddEx(wx, -wy)
Debug.Print "ENT:" & vbTab & wentity
cptEntities += 1
MyEntity.EntityName = wentity
MyEntity.TableName = wtable
Set MyEntityDisplay = MySubModel.EntityDisplays(wentity)
' Set size
MyEntityDisplay.HorizontalSize = ww
MyEntityDisplay.VerticalSize = wh
' Get object ID
If wid <> "" Then
' Get the main color of the object
MyEntityDisplay.BackgroundColor = GetColor(oXml, wid)
End If
End If
ElseIf GetAttributeValue(oneItem, "ColumnName") <> "" Then
' ATTRIBUTE
wattribute = GetAttributeValue(oneItem, "label")
wcolumn = GetAttributeValue(oneItem, "ColumnName")
wdatatype = GetAttributeValue(oneItem, "Datatype")
wnull = UCase(GetAttributeValue(oneItem, "NullOption"))
wpk = UCase(GetAttributeValue(oneItem, "IsPK")) = "TRUE"
' Parse the datatype value
nPos = InStr(wdatatype, "(")
If nPos = 0 Then
datatype = wdatatype
datawidth = 0
Else
datatype = Mid(wdatatype, 1, nPos - 1)
wdatatype = Mid(wdatatype, nPos +1, Len(wdatatype))
nPos = InStr(wdatatype, ")")
s = Mid(wdatatype, 1, nPos - 1)
nSepPos = InStr(s, ",")
If nSepPos = 0 Then
datawidth = Mid(s, 1, nPos - 1)
datascale = 0
Else
datawidth = Mid(s, 1, nSepPos - 1)
datascale = Mid(s, nSepPos + 1, Len(wdatatype))
End If
End If
' Create the Attribute
Set MyAttribute = MyEntity.Attributes.Add(wattribute, wpk)
Debug.Print "ATT:" & vbTab & MyAttribute.AttributeName
cptAttributes += 1
MyAttribute.ColumnName = wcolumn
MyAttribute.Datatype = datatype
MyAttribute.DataLength = datawidth
MyAttribute.DataScale = datascale
MyAttribute.NullOption = wnull
ElseIf GetAttributeValue(oneItem, "RelationshipName") <> "" Then
' RELATIONSHIP
wname = GetAttributeValue(oneItem, "RelationshipName")
wsource = GetAttributeValue(oneItem, "Source")
wtarget = GetAttributeValue(oneItem, "Target")
wrolename = GetAttributeValue(oneItem, "Rolename")
wstyle = GetAttributeValue(oneItem.selectSingleNode("mxCell"), "style")
' Required properties are available
If wname <> "" And wsource <> "" And wtarget <> "" Then
If wrolename = "" Then
' Create the Relationship
' Set MyRelationship = MyModel.Relationships.Add(wsource, wtarget, GetRelationshipType(wstyle))
Set MyRelationship = MyModel.Relationships.AddWithUnification(wsource, wtarget, GetRelationshipType(wstyle))
Else
' Create the Relationship with a specific Attribute name
Set MyRelationship = MyModel.Relationships.AddWithRoleName(wsource, wtarget, GetRelationshipType(wstyle), wrolename)
End If
If Not MyRelationship Is Nothing Then
MyRelationship.Name = wname
Debug.Print "RS: " & vbTab & wname
cptRelationships += 1
End If
End If
Else
' UNKNOWN: Creating shape is possible
wname = GetAttributeValue(oneItem, "label")
' Required properties are available
If wname <> "" Then
Set oneNode = oneItem.selectSingleNode("mxCell").selectSingleNode("mxGeometry")
If Not oneNode Is Nothing Then
wx = CInt(GetAttributeValue(oneNode, "x"))
wy = CInt(GetAttributeValue(oneNode, "y"))
ww = CInt(GetAttributeValue(oneNode, "width"))
wh = CInt(GetAttributeValue(oneNode, "height"))
Else
wx = 0
wy = 0
ww = 0
wh = 0
End If
If ww <> 0 And wh <> 0 Then
Set MyShape = MyModel.Shapes.AddWithPosition(wname, wname, 2, wx, -wy)
Debug.Print "SH: " & vbTab & MyShape.Name
cptShapes += 1
Set MyShapeDisplay = MySubModel.ShapeDisplays(MyShape.Name)
If Not MyShapeDisplay Is Nothing Then
DiagramManager.EnableScreenUpdateEx(True, True)
' Set size
MyShapeDisplay.HorizontalSize = ww
MyShapeDisplay.VerticalSize = wh
' Justification
MyShapeDisplay.HorizontalJustification = 2 ' Center
MyShapeDisplay.VerticalJustification = 2 ' Middle
DiagramManager.EnableScreenUpdateEx(False, False)
End If
End If
End If
End If
Next
#End Region
End If
DiagramManager.EnableScreenUpdateEx(True, True)
MsgBox "Import completed! " & Format((Timer - StartTime) / 86400, "hh:mm:ss") & vbCrLf & vbCrLf & cptEntities & " elements created" & vbCrLf & cptAttributes & " attributes created" & vbCrLf & cptRelationships & " relationships created" & vbCrLf & cptShapes & " shapes created", vbInformation, TITLE
Else
MsgBox "XML can not be loaded!" & vbCrLf & xmlFilename, vbExclamation, TITLE
End If
Exit Sub
Error_detected:
Debug.Print "Error occured!" & IIf(DiagramManager.GetLastErrorCode <> 0, vbCrLf & DiagramManager.GetLastErrorString(), "")
Debug.Print
Resume Next
DiagramManager.EnableScreenUpdateEx(True, True)
End Sub
Private Function GetRelationshipType%(style$)
' Need to be extended with the other shapes you may use
If InStr(style, "endArrow=ERzeroToMany;startArrow=ERzeroToOne;") > 0 Then
GetRelationshipType = 3
ElseIf InStr(style, "endArrow=ERzeroToMany;startArrow=ERmandOne;") > 0 Then
GetRelationshipType = 1
Else
GetRelationshipType = 2
End If
End Function
Private Function GetColor&(ByRef oXml As MSXML2.DOMDocument60, id$)
Dim selectedNodes, node As IXMLDOMNode
Dim s$
GetColor = vbWhite
' Search the nodes linked to the Object
Set selectedNodes = oXml.selectNodes("//mxCell[@parent='" & id & "']")
' Loop through the nodes
For Each node In selectedNodes
s = GetAttributeValue(node, "style")
' s = Mid(s, InStr(s, "strokeColor=") + 13)
s = Mid(s, InStr(s, "fillColor=") + 11)
s = Left(s, InStr(s, ";") - 1)
'Debug.Print s
If Len(s) = 6 Then
GetColor = RGB(Val("&H" & Mid(s, 1, 2)), Val("&H" & Mid(s, 3, 2)), Val("&H" & Mid(s, 5, 2)))
Exit For ' Color has been found
End If
Next node
End Function
Private Function GetAttributeValue$(node As IXMLDOMNode, att$)
'
GetAttributeValue = ""
On Error Resume Next
If Not node.attributes.getNamedItem(att) Is Nothing Then
GetAttributeValue = Trim(node.attributes.getNamedItem(att).text)
End If
End Function
#Region "DialogFunc"
Rem See DialogFunc help topic for more information.
Private Function DlgFunc(DlgItem$, Action%, SuppValue&) As Boolean
Dim fileName$
Dim fileExt$
Select Case Action%
Case 1 ' Dialog box initialization
' DlgText("edFileName", "C:\Users\William\Documents\ERStudio Data Architect 20.1\Tests\GIM.drawio.xml")
Case 2 ' Value changing or button pressed
Select Case DlgItem$
Case "btnSelectFile"
fileName = GetFilePath(,"draw.io XML File (*.xml)|*.xml|All Files (*.*)|*.*",,"Select File", 0)
If (filename <> "") Then
DlgText("edFileName", filename)
End If
DlgFunc = True
Exit Function
Case "btnImport"
DlgEnable("btnImport", False)
DlgEnable("btnExit", False)
DlgEnable("btnSelectFile", False)
filename = DlgText("edFileName")
If Len(filename) = 0 Then
MsgBox "You must specify a file.", vbExclamation, TITLE
DlgFunc = True
Exit Function
Else
If Not FileExists(filename) Then
MsgBox "Specified file does not exist.", vbExclamation, TITLE
DlgFunc = True
Exit Function
Else
fileExt = Right$(filename, Len(filename) - InStrRev(filename, "."))
If (LCase(Left(fileExt, 3)) <> "xml") Then
MsgBox("You can only select an XML file!", vbExclamation, TITLE)
Exit Function
End If
End If
End If
DoImport(fileName)
DlgFunc = False
Exit Function
Case "btnExit"
DlgFunc = False
Exit Function
End Select
Case 3 ' TextBox or ComboBox text changed
Case 4 ' Focus changed
Case 5 ' Idle
Rem DlgFunc = True ' Continue getting idle actions
Case 6 ' Function key
End Select
End Function
#End Region
Private Function FileExists(ByVal fileName As String) As Boolean
FileExists = (Dir(filename) <> "")
End FunctionThis macro utilizes a reference to the Microsoft XML 6.0 library. To add this reference to your macro, follow these steps:
From there, you can locate and select the Microsoft XML 6.0 reference to add it to your macro environment.
The References dialog shows the current macro/module/project’s references. You need to add the Microsoft XML, v6.0 (6.0):
After adding the reference, the macro should run without raising an error for a valid data type.Using this macro with the shared XML file, generates a model like this:
This video shows how to create a macro from a script in ER/Studio Data Architect.
Read our previous related post on importing Logical and Physical Data Models from Microsoft Visio to ER/Studio Data Architect
The macro depends on the data specified on each object. It does the job for this XML file. Using it with your own XML exports would likely require updating the macro as well. The script can be modified to perfectly meet your expectations, or simply copy the parts of this one to your own macros.
For more information on ER/Studio’s Macros, check out our page!
