Beyond The Yellow Bubble

In part 1I discussed the concept of a dataset and how it can be applied to Notes application.  While Notes views are a representation of a dataset I wanted to focus on the opportunities of generating the dataset at run time.  e.g. it becomes possible to take input from the application/user to build the data collection.

Internally, the easiest way to represent a dataset is a NotesDocumentCollection.  One of the issues with this class is there is presently no easy way to store such a dataset, even for the duration of a session.  Nor is there an easy way to display its contents within an application.  Notes provides views/folders as the only effective way of displaying a collection of documents.

1. Views have a number of issues..  The contents of a view are based upon a specified selection formula.  Once created a large amount of server resources are devoted to manitaining the contents of views each and every time the contents of database change.  For this reason the number of views in an application (especially large applications) should always be kept to a practical minimum.
2. Folders seems a much better match for a dynamic run-time dataset as they provide the same basic look/feel but do not carry an overhead to maintan their content.  The process of taking a document collection and adding it toi a view is a very simple one.

The .Domino Framework's DominoDataset class provides a Rebuild method which takes a dataset and gives it a phyiscal form using folders.  We tare then able to mimic the functionality of a datagrid control using the Notes folder control which can be displayed directly or embedded on a form or page.  To maximize flexibility options exist to:-

1. Recognize a dataset that already exists as a view
2. Allow a specific (existing) folder design element to be used.
3. Allow an existing view/folder to be used as a template for a new folder
4. Build a new folder from scratch based upon the field defined in the dataset

 '/**
 ' *  Place the dataset into a folder so that is able to be displayed
 ' */  
 Function Rebuild() As NotesView
  
  Dim Collection As NotesDocumentCollection
  Dim Column  As NotesViewColumn
  Dim Entries  As NotesViewEntryCollection  
  Dim FieldIndex As Integer
  Dim Dataset  As NotesView
  
' Locate exisging view/folder
  
  Set Dataset = iDocument.ParentDatabase.GetView(Me.Foldername$)
  
' For folders, empty the content
  
  If (Not Dataset Is Nothing) Then
   If (Dataset.IsFolder) Then
    Set Entries = Dataset.AllEntries
    Call Entries.RemoveAllFromFolder(Me.Foldername$)
   End If
  End If   
  
' Add documents to folder
  
  If (Dataset.IsFolder) Then
   Set Collection = Me.AllDocuments
   Call Collection.PutAllInFolder(Me.FolderName$)
   Set Dataset = iDocument.ParentDatabase.GetView(Me.Foldername$)
   
' Set folder name and alias
   
   If (Dataset.Aliases(0) <> Me.FolderName$) Then Dataset.Aliases = Me.FolderName$
   If (Dataset.Name <> Me.Title) Then Dataset.Name = Me.Title$
   
' For dynamic folders, refresh design of folder.
'  If a template view is provided, refersh from that else build the folder design based upon the dataset definition.
   
   If (Me.StoreData$ = ENUM_STORE_DATA__DYNAMIC_FOLDER) Then
    If (Me.TemplateView$ = "") Then
     If (Not Isempty(Dataset.Columns)) Then
      Forall ExistingColumn In Dataset.Columns
       Call Dataset.RemoveColumn(ExistingColumn)
      End Forall
     End If
     Forall NewColumn In Me.Fields
      Set Column = Dataset.CreateColumn(Dataset.ColumnCount%+1,Cstr(NewColumn),Cstr(NewColumn))
      Column.Title$ = Me.Label(FieldIndex%)
      If Not (Isnull(Arraygetindex(Me.SortBy,NewColumn))) Then Column.IsSorted = True
      FieldIndex% = FieldIndex% + 1
     End Forall
    Else
     Evaluate(|@UpdateViewDesign("| + Me.FolderName$   + |";"| + Me.TemplateView$ + |")|)
     Call Dataset.Refresh()
    End If
   End If
  End If
  
' Refresh the view/folder
  
  Call Dataset.Refresh()
  Set Rebuild = Dataset
  
 End Function

The following are some of the features that can be added to an application using the dataset/datagrid approach:-

1. Provide the functional equivalence of emedding multiple categories of a view
2. Embed a single category view in which it is still possible to do collapse all/expand all
3. Provide the ability to export data from an application in which a predefined set of rows (documents) & columns (fields) are exported.  The user can also have the option of selecting which of these columns they wish to export.
4. Provide an alternative to views without the overhead of maintaining view contents.  For relative static data folder contents can be rebuilt via a scheduled agent.  Datasets used infrequently can have their content built as part of the folders query open event.
5. Provide a dynamic report buiulding capability
6. Provides an alternate approach to search building in which the use can even define the columns they wish to see in their search results
   

By default Notes only supports the dragging/dropping of documents into a folder.  The following is a technique developed for an application allowing the simulation of dragging a collection of documents into a view:-

• For each view to support drag/drop create a new (dummy) folder.  The design of the folder does not matter as it is never opened/used.
• Modify any outlines used to link to the dummy folder instead of the original view
• Place the following code into the QueryOpen event of each dummy folder forcing the associated view (or page with embedded single category view) to open instead of the folder when selected from the outline.

Sub Queryopen(Source As Notesuiview, Continue As Variant)
    Dim UIW As New NotesUIWorkspace
    Continue = False
    Call UIW.SetTargetFrame("NotesView" )
    Call UIW.CurrentDatabase.OpenView("Viewname" )
    or
    Call UIW.OpenPage("Pagename" )
End Sub

• Modify the database's Postdragdrop event to evaluate continue = false, preventing documents being placed into these dummy folders.
• Finally, add the code to the Postdragdrop event to perform the  desired task for a collection of documents being "dropped in the view".