Chapter 9: Introduction to Working with Databases in Visual Basic

Its Your Turn Exercises Page 376 Questions 5 through 8 are designed for hands-on experience with the material discussed in the text. Comments are added below when appropriate. Completing the remaining questions will enable you to create the Visual Basic project discussed in the text. 1. Start a new project with a single form called frmMemberInfo. Add the controls shown in Figure 9-4, including the data control to the form. (Recall that the graphic of the video camera is found in the Graphics\Icons\Misc folder as Camera.ico and that it goes in an image control.) Give the text box controls the names shown in Table 9-1(txt book); name the data control as datMembers and give it a caption of Members.

Figure 9-4

2. For the data control, the DatabaseName property should be xx:\vintage00.mdb (U may obtained form moodle) and the RecordSource property should be the Members table from this database. Refer below.

3. Set the DataSource property for each of the text boxes to the DatMembers data control and set the DataField property for each text box to the appropriate data field shown in Table 9-1(txtbk). Run your project and verify that the first record of the database is displayed as shown in Figure 9-5. Try out each of the VCR buttons on the data control to browse the database records.

FIG 9-5

4. Create a new Chapter9 folder on your data disk and save the form as MemberInfo.frm and the project as Vintage9.vbp in this folder. Note: VB files for these exercises are saved as Vintage9.vbp, MemberInfo.frm and MemberInfo.frx.

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Questions 5 through 8 are designed for hands-on experience with the material discussed in the text. Comments are added below when appropriate. Completing the remaining questions will enable you to create the Visual Basic project discussed in the text. 5. Add the navigational controls shown in Figure 9-6 along with an Exit button. Use the names and other properties for the navigational buttons shown in Table 9-2(textbook) and cmdExit for the Exit button.

Fig 9-6

6. Add the code shown in VB Code Boxes 9-1, 9-2, and 9-3 for the Form_Activate event procedure and for the cmdFirst and cmdLast navigational buttons. Use the code shown in VB Code Box 9-4 for the imgNext button and the code shown in VB Code Box 9-5 for the imgPrevious button. Finally, add the End statement of the cmdExit button.

VB code 9-1, 9-2, 9-3,9-4 and 9-5 Option Explicit Private Sub Form_Activate() lblRecordNumber.Caption = Str(datMembers.Recordset.AbsolutePosition + 1) End Sub Private Sub cmdFirst_Click() datMembers.Recordset.MoveFirst lblRecordNumber.Caption = Str(datMembers.Recordset.AbsolutePosition + 1) End Sub Private Sub cmdLast_Click() datMembers.Recordset.MoveLast lblRecordNumber.Caption = Str(datMembers.Recordset.RecordCount) End Sub Private Sub imgNext_Click() datMembers.Recordset.MoveNext If Not (datMembers.Recordset.EOF) Then lblRecordNumber.Caption = Str(datMembers.Recordset.AbsolutePosition + 1) Else MsgBox "Already at end of table", vbInformation datMembers.Recordset.MoveLast End If End Sub Private Sub imgPrevious_Click() datMembers.Recordset.MovePrevious If Not (datMembers.Recordset.BOF) Then lblRecordNumber.Caption = Str(datMembers.Recordset.AbsolutePosition + 1) Else MsgBox "Already at beginning of table", vbInformation datMembers.Recordset.MoveFirst End If End Sub Private Sub cmdExit_Click() End End Sub

7. Run your project and try out each of the navigational buttons on the form to browse the database records. Note that the record number changes to match the current record. If you are sure the navigational buttons are working properly, set the Visible property for the datMembers data control to False to make it invisible. 8. Save the form and project under their current names. Note: VB files for these exercises are saved as Vintage9.vbp, MemberInfo.frm and MemberInfo.frx.

Its Your Turn Exercises Page 385 Questions 6 through 14 are designed for hands-on experience with the material discussed in the text. Comments are added below when appropriate. Completing the remaining questions will enable you to create the Visual Basic project discussed in the text. 9. Add a menu bar option to the frmMemberInfo form with a caption of Member Operations and a name of mnuMember. Add submenu options with the captions and names shown in Table 9-4 (Textbook).

Menu bar

10. At the form level, declare blnAddingRecord as a Boolean variable and varCurrentRecord as a String variable.

11. Add the code shown in VB Code Box 9-6 to the mnuMemberAdd event procedure to enable the user to add records to the database. VB Code 9-6 Private Sub mnuMemberAdd_Click() varCurrentRecord = datMembers.Recordset.Bookmark datMembers.Recordset.AddNew blnAddingRecord = True End Sub

12. Add the code shown in VB Code Box 9-7 to the mnuMemberSave event procedure to enable the user to save changes to the database. VB Code 9-7 Private Sub mnuMemberSave_Click() datMembers.UpdateRecord

If blnAddingRecord Then cmdLast_Click blnAddingRecord = False End If End Sub

13. Add the code shown in VB Code Box 9-9 to the mnuMemberCancel event procedure to enable the user to cancel changes to the database. VB Code 9-9 Private Sub mnuMemberCancel_Click() datMembers.UpdateControls If blnAddingRecord Then datMembers.Recordset.Bookmark = varCurrentRecord blnAddingRecord = False End If End Sub

14. Add the code shown in VB Code Box 9-10 to the mnuMemberDelete event procedure to enable the user to delete a record from the database. Vb code 9-10 Private Sub mnuMemberDelete_Click() Const strdelete As String = "Are you sure that you want to delete this record?" Dim intresponse As Integer intresponse = MsgBox(strdelete, vbYesNoCancel + vbCritical + vbDefaultButton2, "Delete Record") If intresponse = vbYes Then datMembers.Recordset.Delete datMembers.Recordset.MoveNext If datMembers.Recordset.EOF Then cmdLast_Click End If End If End Sub

15. Run your project and add the new member discussed in the text (John Lister, with phone number of 770-555-2579, residing at 292 Ashford Way in Bogart, GA 30622). Use the Save Member option to save this new record. 16. Edit the record for Janice Mullins to change her phone number to be 706-555-0778 instead of 706-555-0777. Move to another record and then move back to see that the change has been saved. 17. Save your form and project under the same name. Note: VB files for these exercises are saved as Vintage9.vbp, MemberInfo.frm and MemberInfo.frx.

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Questions 6 through 12 are designed for hands-on experience with the material discussed in the text. Comments are added below when appropriate. Completing the remaining questions will enable you to create the Visual Basic project discussed in the text. 18. Add a list box and command button to the frmMemberInfo form in the lower right-hand area of the form as shown in Figure 9-8. Name the list box lstLateFees and the command button cmdFind. Add a caption of Find Late Fees to the command button.

Figure 9-8

19. Add the code shown in VB Code Box 9-11 to the cmdFind event procedure. Run your project and click the cmdFind command button. You should see the same output as shown in Figure 9-8.

VB Code 9-11 Private Sub cmdFind_Click() Dim strQueryString As String Dim strLateFees As String Dim varBookMark As Variant strLateFees = InputBox("What is the late fees cutoff?") varBookMark = datMembers.Recordset.Bookmark strQueryString = "Late_Fees > " & strLateFees lstLateFees.Clear datMembers.Recordset.FindFirst strQueryString Do Until datMembers.Recordset.NoMatch lstLateFees.AddItem datMembers.Recordset("Name") & _ " " & Format(datMembers.Recordset("Late_Fees"), _ "currency") datMembers.Recordset.FindNext strQueryString Loop datMembers.Recordset.Bookmark = varBookMark End Sub

20. Add a mnuFind menu bar option with a caption of Find to the form. Add three submenu options with the properties shown in Table 9-5.

Menu Find

21. Copy and paste the code from the cmdFind event procedure into the mnuFindLateFees and mnuFindPhoneNumber event procedures you just created. Modify the code for the mnuFindLateFees event procedure to match that shown in VB Code Box 9-12. Finally, add the instruction: lstLateFees.Clear to the mnuFindClear event procedure. VB Code 9-12: Private Sub mnuFindClear_Click() lstLateFees.Clear End Sub Private Sub mnuFindLateFees_Click() Dim strQueryString As String Dim strLateFees As String Dim varBookMark As Variant strLateFees = InputBox("What is the late fees cutoff?") varBookMark = datMembers.Recordset.Bookmark strQueryString = "Late_Fees > " & strLateFees lstLateFees.Clear datMembers.Recordset.FindFirst strQueryString

Do Until datMembers.Recordset.NoMatch lstLateFees.AddItem datMembers.Recordset("Name") & _ " " & Format(datMembers.Recordset("Late_Fees"), _ "currency") datMembers.Recordset.FindNext strQueryString Loop datMembers.Recordset.Bookmark = varBookMark End Sub Private Sub mnuFindPhoneNumber_Click() Const strApos As String = "'" Dim strQueryString As String Dim strPhoneNum As String strPhoneNum = InputBox("What is the Phone Number?") strQueryString = "Phone_Number = " & strApos & strPhoneNum & strApos lstLateFees.Clear datMembers.Recordset.FindFirst strQueryString If datMembers.Recordset.NoMatch Then MsgBox "No match for this phone number", vbExclamation End If lblRecordNumber.Caption = Str(datMembers.Recordset.AbsolutePosition + 1) End Sub

10. Run your procedure and test this submenu option by entering a telephone number of 770-555-1294. Lonnie Stams name, late fees ($2.12), and other information will be displayed in the text boxes. Now enter a telephone number of 706-555-1294. A message that there is no match for this phone number should be displayed. Finally, enter another phone number for a member who is in the database, and verify that the correct name and late fees are displayed. 11. Save your project and form under the current names. Note: VB files for these exercises are saved as Vintage9.vbp, MemberInfo.frm and MemberInfo.frx.