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

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

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

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 Email & Messageing / File System

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

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

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 email properties, etc. are done many times Need a sample of querying

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

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, Email folder objects Contents of a record can be manipulated by the Stream object

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

ADO 2.1 - Object Model Errors Command Parameters Connection Recordset

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

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

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

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) New automation object implemented in ADO 2.5 Models an entity that has a collection of properties and (possibly) nested entities 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) 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.

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

Record Properties

Record Methods

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 A field represents a property associated with a record object 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

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

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 email 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

Supporting Variable Column Recordsets The fields collection on the recordset contains the set of “common” fields From address, subject, receive date, etc. for email 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

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

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 = "http://server02/myfolder/testfolder" rs.Open stSrc, , _ adOpenForwardOnly, _ adLockReadOnly, _ adCmdURLBind rs.MoveNext rec.Open rs End Sub

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=http://adot20/davfs" 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

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 email 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.

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

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)

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

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

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

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

ADO 2.5 - 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

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