March2000

The LA Fox Developer Newsletter

March 2000

Microsoft Windows 2000

Deployment Conference -

April 5, 2000

If you missed the Windows 2000 Conference in San Francisco,

you can experience it right here in Southern California! This one

day conference includes twelve sessions providing in-depth

Windows 2000 technical information focusing on deploying

reliable infrastructure, how to make it easier to use and manage

desktops and servers, and building E-Commerce digital busi-

ness solutions. Special Hands-On theaters will be available all

day so you can test-drive Windows 2000.

Sessions will be presented by Microsoft Systems Engineers as

well as Microsoft Business Partners

The cost for this unique event is $79 per attendee. Attendees

will receive the Microsoft Certified Systems Engineer Training

Kit - Upgrading to Windows 2000, Tech Net IT Guide to Windows

2000, and Windows 2000 Interactive Computer Based Training

CD. Attendees will also be entered to win many exciting prizes

including Windows 2000 Professional, Windows 2000 Server,

Office 2000 and others!

Anaheim Hilton

777 Convention Way

Anaheim, CA 92802

For more information on agenda and detailed breakout descrip-

tions, please visit www.microsoft.com/socal/windows2000/

deploy.

Please visit www.microsoft.com/socal/windows2000/deploy to

limited.

ADO Jumpstart (Con’t from page 4)

ADO recordset is like Pessimistic Locking with Row Buffering in

a Visual FoxPro cursor.

Lock Optimistic—In this scheme, a lock attempt is made when

the Update method is invoked. This locking scheme applies to

both server and client-side recordsets. Optimistic Locking in an

ADO recordset is like Optimistic Locking with Row Buffering in

a Visual FoxPro cursor.

Lock Batch Optimistic — This scheme is like the Lock Optimis-

tic scheme, except that more than one row of data is involved.

In this scheme, a lock is attempted on modified records when

the UpdateBatch method is invoked. This scheme is like

Optimistic Locking with Table Buffering in a Visual FoxPro

cursor.

The following table illustrates the availability of some common

(Con’t, next column)

methods depending on the locking scheme used:

Table 3. Method Availability (Depending on Lock Type)

With the concepts of cursor types, locations, and locking

schemes out of the way, we can discuss the real abilities of

ADO recordsets. The most notable of these abilities are updat-

ing, sorting, and filtering of data. Before undertaking that

discussion, however, take a few moments to review the Fields

Collection object.

Fields collection object

Associated with the Recordset object, is the Fields Collection

object. The Fields Collection object contains zero or more Field

objects. The following code enumerates through the Fields

Collection of a Recordset object:

For Each ofleld In oRecordset.Fields

With oField

?.Name,.Value,.Type,.DefinedSize

?.ActualSlze,.NumericScale,.Precision

End With

Next oField

The common Field properties you will work with:

Name—Specifies the name of the Field object. This corre-

sponds to the name of the data element in the underlying

data source. It is easy to define the name element as the name

of the field in the underlying table. However, note that ADO and

OLE DB work with both relational and nonrelational data. Given

that, while you may be working with ADO, the underlying data

may come from Outlook, Excel, Word, or Windows NT®

Directory Services.

Value-Indicates the current value of the Field object.

OnginalValue—Indicates the Value property of the Field object

before any modifications where made. The OnginalValue

property returns the same value that would be returned by the

Old Val( ) function in Visual FoxPro. When you invoke the

Cancel or CancetUpdate methods of the Recordset object, the

Value property of the Field object is replaced by the contents of

the OriginalValue property. This behavior is similar to that

exhibited when TableRevert( ) is issued against a Visual FoxPro

cursor.

(Con’t, page 8)

Page 6