2. Chapter 8 Relational Databases ActiveX Database Controls 8 Exploring Microsoft Visual Basic 6.0 Copyright © 1999 Prentice-Hall, Inc. By Carlotta Eaton

3. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.2 Objectives... 1. Basic terminology such as tables and relationships 2. Use controls specialized for databases such as the data control, data-bound list box, data-bound combo box, and data- bound grid 3. Differences between FlexGrid control and data-bound grid control

4. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.3 Objectives 4. Implement a front-end application for an existing Access database 5. Use Visual Data Manager 6. Create a new database application with Application Wizard 7. Create new forms with the Data Form Wizard

5. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.4 Overview  Access is the relational database program included with Office Professional Edition  Minimize code using data-bound controls  Use standard ActiveX controls and the FlexGrid control

6. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.5 Relational Databases... Relational databases - composed of tables and relationships Table - consists of rows of records and columns of fields Relationship - association between fields in two tables one-to-one one-to-many many-to-many

7. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.6 Relational Databases... Primary key - field(s) that uniquely determines a record in a database Foreign key - used to defined relationships between tables - a field in a table that also serves as a primary key in another table

8. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.7 Birthday Access Database Birthdays Table Occupations Table Primary Key Foreign Key

9. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.8 Database Controls... Data control - use for each table we want to work with in the database Data control Properties DatabaseName property - path and filename of the existing database RecordSource property - select from the list of tables in the database

10. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.9 Birthday Access Database Data Control for the Occupations Table Data Control for the Birthdays Table

11. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.10 ActiveX Database Controls... Data-bound list control - displays a list box using a database field Data-bound combo control - displays combo box using a database field Data-bound grid control - displays a grid using a database field(s)

12. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.11 ActiveX Database Controls...  Properties to set before utilizing Row Source List Field Text  Properties used to update and manage the database Data Source Data Field Bound Column

13. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.12 ActiveX Database Controls  Properties must be set in order to work correctly 1) Row Source 2) List Field 3) Text Property 4) Data Source 5) Data Field 6) Bound

14. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.13 Database Tools Picture Label Text box Combo box Check box List box Data Image OLE container DBListDBGrid DBCombo

15. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.14 More Properties  Data-bound Grid Control Data Source property  Intrinsic Data-Aware Control Properties Data Source property Data Field property

16. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.15 Birthday Database Using Access Hands-On Exercise 1 Create project, then add and edit forms Add the Data control Edit the module code Edit and verify the Main form code Test the Splash and Main forms Add another Data control, and a Data-bound combo box Test the Data-bound combo control

17. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.16 Managing and Displaying Records Recordset - a record(s) selected from a table(s) in a database Table recordsets - limited to a single table, and can modify records Dynaset recordsets - can be used for multiple tables, and can modify records Snapshot recordsets - can be used for multiple tables, but cannot modify records

18. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.17 Navigating Records with Data Control Methods Name.Recordset.Method Where Name is the name of the data control Method is one of the following: MoveFirst moves to the first record MovePrevious moves to the previous record MoveNext moves to the next record MoveLast moves to the last record Example: datBirthdays.Recordset.MoveFirst

19. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.18 Finding Records with the Data Control Name.Recordset.Method Where Name is the name of the data control Method is one of the following: FindFirst finds the first record FindPrevious finds the previous record FindNext finds the next record FindLast finds the last record Example: datBirthdays.Recordset.FindFirst “LastName = Dion”

20. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.19 Adding and Deleting Records with the Data Control Name.Recordset.Method Where Name is the name of the data control Method is one of the following: AddNew adds a new record to the end of the database Refresh redisplays the current record Update modifies the fields in the current record Delete deletes the current record from the database Close closes the recordset, and frees the memory allocated for storage Example: datBirthdays.Recordset.AddNew

21. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.20 Finish the Birthday Access Project Hands-On Exercise 2 Edit the Module code Test the Add Record and Delete Record code Add code and test the Find Record button and procedure Modify the List form and add the Grid controls Test the List form

22. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.21 More Database Tools...  Different ways to access data ActiveX Data Objects (ADO) Remote Data Objects (RDO) Data Access Objects (DAO)

23. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.22 More Database Tools Learning Edition Tools ActiveX database controls Intrinsic data-aware controls Professional Edition Tools Data View windows (new to VB 6.0) Data Environment Design Data Report feature Enterprise Edition Tools Query Designer Database Designer

24. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.23 Add-Ins Add-ins: tools that are programs that customize and extend the Visual Basic environment 1) Add-ins: generic term 2) Builders: helps view or set control properties 3) Wizards: leads a user step-by-step through a task 4) Utilities: add-in that may be run outside Visual Basic

25. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.24 Visual Data Manager Add a Field Remove a Field

26. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.25 Visual Data Manager and the Birthday Database Hands-On Exercise 3 Create a new project & new database Create a new table and add fields Add a record to the database Use the Application Wizard Use the Data Form Wizard Finish the Application Wizard Test the Update form and the Grid form

27. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.26 Summary...  Access included with Microsoft Office Professional Edition  Relational databases composed of several tables and relationships  Relationships established between two tables using a foreign key

28. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.27 Summary...  ActiveX database controls include Data-bound list box Data-bound combo box Data-bound grid control FlexGrid control  Data control must be used for each table we want to access

29. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.28 Summary...  Navigate database using recordsets Table recordset Dynaset recordset Snapshot recordset  Define new databases using the Visual Data Manager add-in included in all 3 editions of Visual Basic

30. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.29 Summary  Data Form Wizard (new with VB 6.0) helps create database forms  Application Wizard creates general forms such as Splash and About forms for applications

31. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.30 Practice with Visual Basic 1. Demonstration: Data Browser Program 2. Sample Program: Bibliography Database Browser 3. Demonstration: Music Review Notepad 4. Personal Address Book 5. Access Demo 6. Access Demo Front End

32. Exploring MS Visual Basic 6 Copyright 1999 Prentice-Hall, Inc.31 Case Studies  Relational Database Design  Database Design Implementation  Access Office VB Advisor  Universal Access Web Site