1. What’s new in ADO 2.5 Greg Hinkel Program Manager Data Access Group greghin@microsoft.com

3. Agenda ADO - Overview Semi-structured Data URL binding for ADO Objects
Record Object
Stream Object
Performance and XML
Summary
Feedback and Information

4. ADO Overview
A single, powerful consumer interface for data exposed by OLE DB providers
For use in Web-based, Client/Server and distributed applications
Works with many languages (Visual Basic®, Visual C++®, Visual J++™, Visual Basic Scripting Edition)
High Performance
Simple Object Model

5. MDAC Components
IIS / VS / IE / MTS / ETC
ASP / ISAPI
ADO
OLEDB Core Services
Shape Provider
OLEDB Providers
XML
Oracle
SQL Server
ODBC
MDAC
ODBC Drivers - SQL Server - Oracle - Etc
Backend Data Store Mainframe / RDBMS / Directory & Messageing / File System

6. Semi-structured data Data that is: Examples:
More structured than a BLOB
Structured differently than a relational database table
Examples:
A file system
data
Web pages

7. Semi-structured data
Data that may be organized hierarchically, like a tree
Can have arbitrary depth
Each node in the tree has a set of properties
Each node may have a different set of properties
Leaf-nodes associated with a special “Value” property
Non-leaf nodes are collections of other nodes

8. Semi-structured Requirements
Node Operations
Get/Set properties, Add/Delete properties
Scoped Operations
Move, Copy, Delete operations apply to all contained nodes
Querying
A list of nodes that satisfy a predicate on properties
Lightweight
Operations such as reading properties, etc. are done many times
Need a sample of querying

9. ADO 2.5 - Design Goals Keep it simple!
Allow ADO objects to be opened with URL strings
Extend ADO to work with hierarchical data sources
Provide the ability to do scoped operations
Extend ADO so that it may be used to read and manipulate binary streams

10. Modeling semi-structured data with ADO 2.5
Collections are modeled as recordsets
Common properties are modeled as fields of the recordset
Folders, Directories
Nodes are modeled as a record object
Properties are modeled as fields of the record object
Files, folder objects
Contents of a record can be manipulated by the Stream object

11. Semi-Structured Data in MDAC 2.5
Resources Collections Properties
OLE DB 2.5
Row Rowset Columns
ADO 2.5
Record Recordset Fields

12. ADO Object Model
Errors
Command
Parameters
Connection
Recordset

13. ADO 2.5 - Object Model Errors Command Parameters Connection Recordset
Fields
Record
Stream

14. URL Naming for ADO
URLs can be used to directly identify objects in a data source
nodes in a hierarchical namespace (files and folders)
table in a relational database, unique rows in a table
Record object represents a unique object
file, folder, table, row
Recordset object represents the contents of a collection object
rows of a table, files in a folder
Follow with a slide that has brief samples

15. URL binding in ADO 2.5 ADO 2.5 allows URL naming for
Connection, Recordset, Record, and Stream objects
For a Recordset, URL must point to a collection type node
For stream, URL must point to an object with a default stream defined
The RootBinder cracks URLs and calls the right provider
New record objects can also be created directly

16. URL naming - sample code
Sub main()
Dim conn As New Connection
Dim rec As New Record, rec2 As New Record
‘open a connection and then the record
‘URL= in the connection string
conn.Open "URL=
rec.Open "TestFolder", conn
‘open record with implicit connection object
‘URL= only in the connection string
rec2.Open " TestFolder ", _ "URL=
End Sub

17. Record Object (1 of 2) New automation object implemented in ADO 2.5
Models an entity that has a collection of properties and (possibly) nested entities
, Files, web pages, structured documents, folders, Databases, Tables, etc.
can also represent a row of a recordset
/File contents appear as a stream property

18. Record Object (2 of 2) Expresses the notion of containment & scoping
Folders contain other folders and files
Folder operations such as move, copy, etc. apply within the folder’s scope
Properties are modeled as a collection of Fields
Containment is modeled as Sub-Records
Records can be viewed in a tabular form as a recordset
Properties and methods are implemented to operate on the record object
Records can be viewed in tabular form as a recordset either by opening the recordset with a collection or by using Record.GetChildren.

19. Opening a Record Object
Many ways to open a record object
Open directly using a URL that uniquely identifies it
From an ADO recordset by specifying an individual record
From a field’s value property
Record object always exists in the context of a Connection object
connection object is either implicitly created or explicitly specified

20. Record Properties

21. Record Methods

22. The Record Object
‘opens an existing record object or creates a new one
Sub OpenFolderIfExists()
Dim rec As New Record
Dim rs As Recordset
rec.Open "TestFolder", _ "URL=
if rec.RecordType = adRecCollection then
Set rs = rec.GetChildren
‘do stuff with recordset
end if
End Sub

23. Fields of a Record object
A field represents a property associated with a record object
Title, size, modified time of a file, folder, message
Fields are implemented as a collection on the record object
Methods and properties are same as that on recordset’s field object
New fields can be added to the collection of an already open record object

24. The Recordset Object
When a record is a collection (such as a folder), it has other records contained in it
A view of contained records is available as a recordset
tabular view as opposed to the tree view
Use GetChildren method on the Record object
opens the default contents recordset - pre-defined schema for document source providers
Execute a command against a folder
Ability to search on properties
Use Record and Recordset for navigation
URL is one of the fields on the contents recordset & can be used to open the contained records

25. Recordsets with Variable # of Columns
Many data sources generate recordsets where each row has a different set of columns
Case in point: Contents of a mail folder
An folder has different properties from the Contacts folder
Case in point: An XML stream
Each element may have a different set of attributes
Case in point: The Contents recordset
Each file in a folder has different set of properties

26. Supporting Variable Column Recordsets
The fields collection on the recordset contains the set of “common” fields
From address, subject, receive date, etc. for
File name, size, last modified, etc. for files
Each record has a set of fields unique to that row
This is a superset of the common columns that exist for the recordset
To view the variable fields, obtain a record object from the recordset and then use its fields collection

27. Relationship between the Record & Recordset Objects
Record’s field collection
Superset of the fields collection on the associated source recordset, if any
It is possible to add/delete fields from an already open record object
only for fields that are unique to that record
Record behaves in the same update mode as its source recordset
if no source recordset, then in immediate update mode

28. Working with the Recordset Object
'open Recordset
Sub OpenRecordset()
Dim rs As New ADODB.Recordset
Dim rec As New ADODB.Record
Dim cn As New ADODB.Connection
stSrc = "
rs.Open stSrc, , _
adOpenForwardOnly, _
adLockReadOnly, _
adCmdURLBind
rs.MoveNext
rec.Open rs
End Sub

29. Working with the Fields collection
Sub RSFields()
Dim rs As New Recordset
Dim rec As New Record
Dim fld As Field
Dim strURL As String
strURL = "URL=
rs.Open "greghin", strURL, , , adCmdTableDirect
While Not rs.EOF
rec.Open rs
For Each fld In rec.Fields
Debug.Print fld.Name, " = ", fld.Value
Next
rec.Close
rs.MoveNext
Wend
End Sub

30. Stream Object
An automation object used to manipulate the contents of a binary or textual stream
Implemented on top of IStream interface
Record objects usually have a default stream associated with them
content of an message, default document for a web folder
BLOB/Text fields in a database may also be viewed as a stream object
Non collection records usually have a default stream associated with them.

31. Stream Properties (1 of 2)
Charset: Specifies the character set into which the contents of a text Stream should be translated
EOS: Identifies whether the current position is at the end of the stream
LineSeparator: Specifies the character to be used as the line separator in a text stream
Mode: Indicates the available permissions for modifying data in a Stream object

32. Stream Properties (2 of 2)
Position: Specifies the current position within a Stream object
Size: Indicates the total size of the stream in number of bytes
State: Indicates whether the object is open or closed
Type: Identifies the type of data contained in the Stream (binary or text)

33. Stream Methods (1 of 2)
Cancel: Cancels an asynchronous operation on the stream object
Close: Take a guess
CopyTo: Copies a specified number of bytes from a stream to another stream object
Flush: Forces the contents of the Stream remaining in the ADO buffer to the underlying object with which the Stream is associated
LoadFromFile: Loads the contents of a file by reading in data from an existing file
Open: Opens a Stream object to manipulate streams of binary or text data

34. Stream Methods (2 of 2)
Read: Reads a specified number of bytes from a Stream object
ReadText: Reads specified number of characters from a text Stream object
SaveToFile: Saves the contents of a stream into a specified file
SetEOS: Sets the position that is the end of the stream
SkipLine: Skips one entire line when reading a text stream
Write: Writes binary data to a Stream object
WriteText: Writes a specified text string to a Stream object

35. Working with the Stream object
Sub StrmOperations()
Dim strm As New Stream
strm.Open "URL=
Debug.Print strm.Size
Debug.Print strm.Type 'adStructDoc = 2
Debug.Print strm.ReadText
Debug.Print strm.Charset 'Unicode
strm.SaveToFile "C:\CopyOfDoc.doc"
End Sub

36. Performance ADO 2.5 is faster than ADO 2.1
We improved our performance for scripting languages
Much better on multiple processor machines

37. XML ASP File Stream rs.Save Response, adPersistXML rs.Open Request
rs.Save “C:\authors.xml”, adPersistXML
rs.Open “C:\authors.xml”, adPersistXML
Stream
rs.Save strm, adPersistXML
rs.Open strm

38. ADO Summary
Extends ADO to work with semi-structured data exposed by new data sources
Enables web-publishing and document management through scripting languages
Shipping MDAC 2.5 with Windows 2000
Available in Beta3

39. Feedback and Information
Newsgroups and web site:
microsoft.public.data.oledb
microsoft.public.data.ado
microsoft.public.data.ado.rds
Feedback
MDAC:
ADO:
OLE DB:
ODBC: