Introduction to Visual FoxPro

Ted Roche

Ted Roche & Associates, LLC

Ground Rules

Pagers and cell phones silent, please.

Rest breaks as appropriate

How to ask questions

Administrivia

Conference Binder

Schedule – Some sessions only given once

Trade Show – T-shirt Tuesday, Drawing Wed.

Evaluations - help the community

Closing session questions – Wednesday noon

Drink Tickets!

Goals for this morning

Learn the terminology used in VFP

Understand the tools of VFP has

Understand how VFP stores and retrieves data

Know what applications VFP can create

Know resources to learn more

Who is Ted Roche?

President of TR&A, LLC Consulting

Microsoft Certified Solution Developer,
Microsoft Certified Systems Engineer

Co-Author of Hacker’s Guide to VFP 6

Author of Essential SourceSafe

Microsoft Support MVP

Outline

Ground Rules & Pop Quiz

Episode I: It’s the Data

Part B: It’s the Coding

Act III: Advanced Topics

Part 4: Putting it all together

Epilogue: So, Now What?

What is Visual FoxPro?

Visual FoxPro is…

… a standalone tool for data manipulation.

… a development tool for standalone, LAN, client-server, COM and Web applications.

… a database engine.

… a programming language.

… part of Visual Studio.

… an integral part of Microsoft Windows.

… a religion.

Slide 7

Episode I:
It’s the Data

Episode I: It’s the Data

Terminology

Data Design

Normalization

Reading and Writing Data

Transactions and Buffering

Client-Server Data

Terminology

Field: single piece of data

Datatype: describes contents and limits

Record: single piece of information

Table: set of records

Cursor: CURrent Set Of Records

Data Design

What goes where?

Typically, data is assigned to table that represent entities

For example, customer, item, video, dancer

Caution: table entities may not be objects!

Field datatypes are chosen to represent data

Data are assigned to the entities owning them

Normalization

Why Be Normal?

Easy applications from well-designed data,
poorly designed data makes for tough apps

Primary Key (PK) uniquely defines record (1^st)

All parts of PK required to identify record (2^nd)

No other fields needed for uniqueness (3^rd )

When a record wants to refer to another, it stores the PK of that record. That field is a foreign key (FK)

Relational Data

Different tables are related to one another with primary and foreign key matches.

Ex. Sales order table holds customer FK

Relationships may be:

(Zero or) One-to-one

(Zero or) One-to-Many

Self-join

Relational Integrity (RI) can be enforced with triggers, RI Builder, or code

Ex. Cannot delete invoice with detail items

Reading and Writing Data

Interactive or Programmatic VFP Commands

REPLACE

APPEND (BLANK)

BROWSE / EDIT

DELETE

COPY

SQL Commands

INSERT

UPDATE

DELETE

Transactions and Buffering

Data on disk should always be complete and consistent.

Buffering allows you to make a series of changes, and have the data in local cursors until you are ready to commit it.

Transactions allow you to lock the affected records from the time you start and update until you complete it.

Client-Server Data

Use Client-Server for low-bandwidth, high security, large amounts of data, or high availability situations

Remote Views

Direct ODBC Functions

SQLConnect(), SQLExecute()

Data appears in VFP as a cursor

Questions on Data?

Terminology

Data Design

Normalization
Reading and Writing Data

Transaction and Buffering

Client-Server Data

Part B:
It’s the Coding

Part B: It’s the Coding

VFP Commands & Functions

Controls, Forms, Classes & Objects

Event Model

The VFP Toolset:

Project Manager

Form and Class Designer

Code Editor

… and many more

VFP Commands

Commands stand alone, functions return values

Structural: DO WHILE, IF, DO CASE

Data: REPLACE, APPEND, DELETE

I/O: @…SAY, LIST, REPORT

Functions:

Controls, Forms, Classes & Objects

Controls are the widgets that display stuff, present actions for the operator to take

Forms are where you place your controls

Classes are the templates for your objects

Objects are the instantiated (running) entities based on classes.

Event Model

Init() initializes, Destroy() at end

Exception: Form’s DE before form

Error() traps all errors in an object’s code

Activate() and Deactivate() events on focus

Mouse* on mouse events – up, down, move

OLE Drag and Drop supported with a series of events

Events fire automatically, or when the user chooses – use events to fire code in methods, never methods to call events.

VFP Toolset

Project Manager

Form and Class Designer

Code Editor

Questions on Part B: Coding?

VFP Commands

Controls, Forms, Classes & Objects

Event Model

The VFP Toolset:

Project Manager

Form and Class Designer

Code Editor

… and many more

Act III:
Advanced Topics

Act III: Advanced Topics

Object-oriented analysis and design

N-tier Design

COM, DCOM, COM+

ADO and ODBC

User Interface Design

Project Management

Object Oriented Analysis & Design

RTFM!

Objects are containers of consistent behavior and the data needed for those behaviors

Encapsulation – behavior & data

Polymorphism – same name, different behavior

Inheritance – overwrite the exceptions only

Composition – use groups of objects to form complex behaviors – basis for GOF Patterns

N-Tier Design

An n-tier design is any set of components communicating via well-defined interfaces

Classic monolithic coding is single (really zero) tier

Client-server is two-tier

Web apps are often three (interface management « business logic « data mgmt

Programming to interface is difficult but more flexible, scalable and powerful

COM, DCOM, COM+

Microsoft’s means of managing components

Publish interfaces for others to consume

Pool object in transaction services

Heavyweight framework with runtime expenses

ADO and ODBC

ADO – Active Data Objects – high-level COM layers on OLE DB interface to data

ODBC – more primitive, less scalable and manageable interface to data

ODBC supported natively in VFP’s Remote Views and Connections, SQL* functions

ADO can be interfaced to VFP

VFP 7 first with OLE-DB provider for VFP data

User Interface Design

Simpler is better

Programmers typically do not have the proper mindset for good user interface design

When in doubt, borrow from the work of others

Study the resources available ACM-HCI

Least expensive tool: watch an operator run your application.

Project Management

There are no silver bullets – Fredrick P. Brooks

There are, however, engineering principles:

Estimate it

Measure it

Plan it

Manage it

There are methodologies out there (RUP, Agile, Crystal, Extreme) learn and use them

Questions on Act III: Advanced Topics

Object-oriented analysis and design

N-tier Design

COM, DCOM, COM+

ADO and ODBC

User Interface Design

Project Management

Part 4:
Putting It All Together

Part 4: Putting It All Together

Read The Fine Manuals

Be One With The Fox

Use A Framework

Get A Support Group

Sharpen The Saw

Top Ten Mistakes

Read The Fine Manuals

VFP Manuals are among the best in Microsoft!

The Help file is huge!

There are many fine 3^rd party books

Check out the magazines – Foxtalk,FPA, Code

99% of the questions answered on the forums come right out of one of these sources

Be One With The Fox

When you choose to ride the tiger,
you must go where the tiger goes

Learn the FoxPro Way of coding

Use A Framework

Frameworks have 3 – 10 man-years of effort, large customer base, varied applications

Unlike your own framework, or sample code, these have been tested in the real world

Customer support available

Manuals and tutorials

Get A Support Group

How many have solved a problem by explaining it to someone else?

On-line forums: UT, CompuServe, FoxForum.com

Newsgroups: Microsoft and uunet

User Groups: monthly, free (or cheap), networking opportunity

Sharpen The Saw

None of us know it all (except maybe Calvin)

Improve your development and consulting techniques by:

Attending conferences

Reading journals

Participating online

Reading books (in and out of the industry)

Top Ten Mistakes

It ran fine on my system!

It worked great with ten records!

I could write that in a week!

We’re just converting an existing system – two weeks, maybe four weeks, max!

Our situation is unique…

Top Ten Mistakes

We don’t have time to document it now…

I know how the system should work…

Upper management has no idea what we do.

But, what if….

Those who fail to learn from the past…

… are bound to be past by those of us who have!

Questions on Part 4:
Putting It All Together

Read The Fine Manuals

Be One With The Fox

Use A Framework

Get A Support Group

Sharpen The Saw

Top Ten Mistakes

Epilogue: So, Now What?

DevCon is a great opportunity to:

Learn an awful lot about FoxPro

Learn about emerging technologies

Network for business opportunities

Have some fun!

Go for it!

When you get back home, review your notes, check the web site for updates, and dig up some of the resources provided here.

ADVISOR DEVCON Web Update Page

http://www.Advisor.com/CMF0109p.nsf/w/vfppre

This session WILL / WILL NOT

have updates.

"Thank you!"

Thank you!

Please remember to fill out your evaluation.


	Pagers and cell phones silent, please.
	Rest breaks as appropriate
	How to ask questions
	Administrivia
		Conference Binder
		Schedule – Some sessions only given once
		Trade Show – T-shirt Tuesday, Drawing Wed.
		Evaluations - help the community
		Closing session questions – Wednesday noon
		Drink Tickets!


	Learn the terminology used in VFP
	Understand the tools of VFP has
	Understand how VFP stores and retrieves data
	Know what applications VFP can create
	Know resources to learn more


	President of TR&A, LLC Consulting
	Microsoft Certified Solution Developer, Microsoft Certified Systems Engineer
	Co-Author of Hacker’s Guide to VFP 6
	Author of Essential SourceSafe
	Microsoft Support MVP


	Ground Rules & Pop Quiz
	Episode I: It’s the Data
	Part B: It’s the Coding
	Act III: Advanced Topics
	Part 4: Putting it all together
	Epilogue: So, Now What?


	Visual FoxPro is…
	… a standalone tool for data manipulation.
	… a development tool for standalone, LAN, client-server, COM and Web applications.
	… a database engine.
	… a programming language.
	… part of Visual Studio.
	… an integral part of Microsoft Windows.
	… a religion.


	Terminology
	Data Design
	Normalization
	Reading and Writing Data
	Transactions and Buffering
	Client-Server Data


	Field: single piece of data
	Datatype: describes contents and limits
	Record: single piece of information
	Table: set of records
	Cursor: CURrent Set Of Records


	What goes where?
	Typically, data is assigned to table that represent entities
		For example, customer, item, video, dancer
		Caution: table entities may not be objects!
	Field datatypes are chosen to represent data
	Data are assigned to the entities owning them


	Why Be Normal?
		Easy applications from well-designed data, poorly designed data makes for tough apps
	Primary Key (PK) uniquely defines record (1^st)
	All parts of PK required to identify record (2^nd)
	No other fields needed for uniqueness (3^rd )
	When a record wants to refer to another, it stores the PK of that record. That field is a foreign key (FK)


	Different tables are related to one another with primary and foreign key matches.
		Ex. Sales order table holds customer FK
	Relationships may be:
		(Zero or) One-to-one
		(Zero or) One-to-Many
		Self-join
	Relational Integrity (RI) can be enforced with triggers, RI Builder, or code
		Ex. Cannot delete invoice with detail items


	Interactive or Programmatic VFP Commands
		REPLACE
		APPEND (BLANK)
		BROWSE / EDIT
		DELETE
		COPY
	SQL Commands
		INSERT
		UPDATE
		DELETE


	Data on disk should always be complete and consistent.
	Buffering allows you to make a series of changes, and have the data in local cursors until you are ready to commit it.
	Transactions allow you to lock the affected records from the time you start and update until you complete it.


	Use Client-Server for low-bandwidth, high security, large amounts of data, or high availability situations
	Remote Views
	Direct ODBC Functions
		SQLConnect(), SQLExecute()
	Data appears in VFP as a cursor


	Terminology
	Data Design
	Normalization Reading and Writing Data
	Transaction and Buffering
	Client-Server Data


	VFP Commands & Functions
	Controls, Forms, Classes & Objects
	Event Model
	The VFP Toolset:
		Project Manager
		Form and Class Designer
		Code Editor
		… and many more


	Commands stand alone, functions return values
	Structural: DO WHILE, IF, DO CASE
	Data: REPLACE, APPEND, DELETE
	I/O: @…SAY, LIST, REPORT
	Functions:


	Controls are the widgets that display stuff, present actions for the operator to take
	Forms are where you place your controls
	Classes are the templates for your objects
	Objects are the instantiated (running) entities based on classes.


	Init() initializes, Destroy() at end
		Exception: Form’s DE before form
	Error() traps all errors in an object’s code
	Activate() and Deactivate() events on focus
	Mouse* on mouse events – up, down, move
	OLE Drag and Drop supported with a series of events
	Events fire automatically, or when the user chooses – use events to fire code in methods, never methods to call events.


	VFP Commands
	Controls, Forms, Classes & Objects
	Event Model
	The VFP Toolset:
		Project Manager
		Form and Class Designer
		Code Editor
		… and many more


	Object-oriented analysis and design
	N-tier Design
	COM, DCOM, COM+
	ADO and ODBC
	User Interface Design
	Project Management


	RTFM!
	Objects are containers of consistent behavior and the data needed for those behaviors
	Encapsulation – behavior & data
	Polymorphism – same name, different behavior
	Inheritance – overwrite the exceptions only
	Composition – use groups of objects to form complex behaviors – basis for GOF Patterns


	An n-tier design is any set of components communicating via well-defined interfaces
	Classic monolithic coding is single (really zero) tier
	Client-server is two-tier
	Web apps are often three (interface management « business logic « data mgmt
	Programming to interface is difficult but more flexible, scalable and powerful


	Microsoft’s means of managing components
	Publish interfaces for others to consume
	Pool object in transaction services
	Heavyweight framework with runtime expenses


	ADO – Active Data Objects – high-level COM layers on OLE DB interface to data
	ODBC – more primitive, less scalable and manageable interface to data
	ODBC supported natively in VFP’s Remote Views and Connections, SQL* functions
	ADO can be interfaced to VFP
	VFP 7 first with OLE-DB provider for VFP data


	Simpler is better
	Programmers typically do not have the proper mindset for good user interface design
	When in doubt, borrow from the work of others
	Study the resources available ACM-HCI
	Least expensive tool: watch an operator run your application.


	There are no silver bullets – Fredrick P. Brooks

	There are, however, engineering principles:
	Estimate it
	Measure it
	Plan it
	Manage it
	There are methodologies out there (RUP, Agile, Crystal, Extreme) learn and use them


	Read The Fine Manuals
	Be One With The Fox
	Use A Framework
	Get A Support Group
	Sharpen The Saw
	Top Ten Mistakes


	VFP Manuals are among the best in Microsoft!
	The Help file is huge!
	There are many fine 3^rd party books
	Check out the magazines – Foxtalk,FPA, Code
	99% of the questions answered on the forums come right out of one of these sources


	When you choose to ride the tiger, you must go where the tiger goes

	Learn the FoxPro Way of coding


	Frameworks have 3 – 10 man-years of effort, large customer base, varied applications
	Unlike your own framework, or sample code, these have been tested in the real world
	Customer support available
	Manuals and tutorials