What’s new in ADO 2.5
Greg Hinkel
Program Manager
Data Access Group
greghin@microsoft.com
Agenda
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ADO - Overview
Semi-structured Data
URL binding for ADO Objects
Record Object
Stream Object
Performance and XML
Summary
Feedback and Information
ADO Overview
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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
MDAC Components
IIS / VS / IE / MTS / ETC
ASP / ISAPI
ADO
OLEDB Core Services
Shape
Provider
MDAC
OLEDB Providers
XML
Oracle
SQL Server
ODBC
ODBC Drivers
- SQL Server
- Oracle
- Etc
Backend Data Store
Mainframe / RDBMS / Directory
Email & Messageing / File System
Semi-structured data
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Data that is:
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More structured than a BLOB
Structured differently than a relational
database table
Examples:
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A file system
Email data
Web pages
Semi-structured data
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Data that may be organized
hierarchically, like a tree
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Each node in the tree has a set of
properties
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Can have arbitrary depth
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
Semi-structured Requirements
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Node Operations
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Scoped Operations
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Move, Copy, Delete operations apply to
all contained nodes
Querying
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Get/Set properties, Add/Delete properties
A list of nodes that satisfy a predicate on
properties
Lightweight
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Operations such as reading email
properties, etc. are done many times
ADO 2.5 - Design Goals
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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
Modeling semi-structured
data with ADO 2.5
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Collections are modeled as recordsets
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Nodes are modeled as a record object
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Common properties are modeled as
fields of the recordset
Folders, Directories
Properties are modeled as fields of the
record object
Files, Email folder objects
Contents of a record can be
manipulated by the Stream object
Semi-Structured Data in
MDAC 2.5
Semi-Structured Data
Resources
Collections
Properties
Rowset
Columns
Recordset
Fields
OLE DB 2.5
Row
ADO 2.5
Record
ADO 2.1 - Object Model
Errors
Command
Connection
Recordset
Parameters
ADO 2.5 - Object Model
Errors
Command
Connection
Recordset
Record
Parameters
Fields
Stream
URL Naming for ADO
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URLs can be used to directly identify
objects in a data source
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Record object represents a unique
object
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nodes in a hierarchical namespace (files
and folders)
table in a relational database, unique
rows in a table
file, folder, table, row
Recordset object represents the
contents of a collection object
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rows of a table, files in a folder
URL binding in ADO 2.5
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ADO 2.5 allows URL naming for
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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
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=http://adot20/davfs/greghin"
rec.Open "TestFolder", conn
‘open record with implicit connection object
‘URL= only in the connection string
rec2.Open " TestFolder ", _
"URL=http://adot20/davfs/greghin/“
End Sub
Record Object (1 of 2)
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New automation object implemented
in ADO 2.5
Models an entity that has a collection
of properties and (possibly) nested
entities
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Email, Files, web pages, structured
documents, folders, Databases, Tables,
etc.
can also represent a row of a recordset
Email/File contents appear as a stream
property
Record Object (2 of 2)
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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
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Records can be viewed in a tabular form as a
recordset
Properties and methods are implemented to
operate on the record object
Opening a Record Object
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Many ways to open a record object
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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
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connection object is either implicitly
created or explicitly specified
Record Properties
ActiveConnection Identifies the active connection object
associated with the current record
State
Current state of the record object
Source
URL string used to open the record
object
Mode
Access mode for the record object
ParentURL
URL string identifying the parent node
of the current record object
RecordType
Type of the current record object –
simple document, collection, structured
document
Record Methods
Open
Opens an existing record object or creates
a new one using URL, a connection string,
or a recordset object
Close
Closes an already open record object
Cancel
Cancels an aynchronous operation on the
recordset
CopyRecord
Copies a sub-record and its children to a
new location
MoveRecord
Moves a sub-record and its children to a
new location
DeleteRecord
Deletes a sub-record and its children
GetChildren
Opens a recordset containing the child
nodes of the current record object
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=http://adot20/davfs/greghin/“
if rec.RecordType = adRecCollection then
Set rs = rec.GetChildren
‘do stuff with recordset
end if
End Sub
Fields of a Record object
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A field represents a property
associated with a record object
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Title, size, modified time of a file, folder,
email 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
Working with the Fields
collection
Sub RSFields()
Dim rec As New Record
Dim fld As Field
rec.Open "greghin", "URL=http://adot20/davfs"
‘use For Each to loop all the fields
For Each fld In rec.Fields
Debug.Print fld.Name, " = ", fld.Value
Next
End Sub
The Recordset Object
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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
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Use GetChildren method on the Record
object
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opens the default contents recordset - predefined schema for document source providers
Execute a command against a folder
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tabular view as opposed to the tree view
Ability to search on properties
Use Record and Recordset for navigation
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URL is one of the fields on the contents
recordset & can be used to open the contained
records
Recordsets with Variable # of
Columns
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Many data sources generate recordsets
where each row has a different set of
columns
Case in point: Contents of a mail folder
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Case in point: An XML stream
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An email folder has different properties from the
Contacts folder
Each element may have a different set of
attributes
Case in point: The Contents recordset
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Each file in a folder has different set of
properties
Supporting Variable Column
Recordsets
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The fields collection on the recordset
contains the set of “common” fields
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Each record has a set of fields unique to
that row
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From address, subject, receive date, etc. for
email
File name, size, last modified, etc. for files
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
Relationship between the
Record & Recordset Objects
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Record’s field collection
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It is possible to add/delete fields from
an already open record object
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Superset of the fields collection on the
associated source recordset, if any
only for fields that are unique to that
record
Record behaves in the same update
mode as its source recordset
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if no source recordset, then in immediate
update mode
Working with the Recordset
Object
Sub OpenRecordset()
Dim rs As New Recordset
Dim rec As New Record
rs.Open "greghin", "URL=http://adot20/davfs", _
, , adCmdTableDirect
While Not rs.EOF
rec.Open rs
Debug.Print rec("RESOURCE_PARSENAME").Name
rec.Close
rs.MoveNext
Wend
End Sub
Stream Object
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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
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content of an email message, default
document for a web folder
BLOB/Text fields in a database may
also be viewed as a stream object
Stream Properties (1 of 2)
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Charset: Specifies the character set
into which the contents of a text
Stream should be translated
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EOS: Identifies whether the current
position is at the end of the stream
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LineSeparator: Specifies the
character to be used as the line
separator in a text stream
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Mode: Indicates the available
permissions for modifying data in a
Stream object
Stream Properties (2 of 2)
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Position: Specifies the current
position within a Stream object
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Size: Indicates the total size of
the stream in number of bytes
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State: Indicates whether the
object is open or closed
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Type: Identifies the type of data
contained in the Stream (binary or
text)
Stream Methods (1 of 2)
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Cancel: Cancels an asynchronous operation
on the stream object
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Close:
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CopyTo: Copies a specified number of bytes
from a stream to another stream object
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Flush: Forces the contents of the Stream
remaining in the ADO buffer to the underlying
object with which the Stream is associated
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LoadFromFile: Loads the contents of a file
by reading in data from an existing file
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Open: Opens a Stream object to manipulate
streams of binary or text data
Take a guess
Stream Methods (2 of 2)
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Read: Reads a specified number of bytes from a
Stream object
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ReadText: Reads specified number of
characters from a text Stream object
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SaveToFile: Saves the contents of a stream
into a specified file
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SetEOS: Sets the position that is the end of the
stream
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SkipLine: Skips one entire line when reading a
text stream
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Write: Writes binary data to a Stream object
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WriteText: Writes a specified text string to a
Stream object
Working with the Stream
object
Sub StrmOperations()
Dim strm As New Stream
strm.Open "URL=http://adot20/davfs/greghin/some.doc"
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
Performance
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ADO 2.5 is faster than ADO 2.1
We improved our performance for
scripting languages
Much better on multiple processor
machines
XML
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ASP
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File
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rs.Save Response, adPersistXML
rs.Open Request
rs.Save “C:\authors.xml”, adPersistXML
rs.Open “C:\authors.xml”, adPersistXML
Stream
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rs.Save strm, adPersistXML
rs.Open strm
ADO 2.5 - Summary
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Extends ADO to work with semistructured data exposed by new data
sources
Enables web-publishing and
document management through
scripting languages
Shipping MDAC 2.5 with Windows
2000
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Available in Beta3
Feedback and Information
Newsgroups and web site:
 http://www.microsoft.com/data/
 microsoft.public.data.oledb
 microsoft.public.data.ado
 microsoft.public.data.ado.rds
Feedback
 MDAC: mdac@microsoft.com
 ADO: adodoc@microsoft.com
 OLE DB: oledbdoc@microsoft.com
 ODBC: odbcdoc@microsoft.com