Learn To Program Databases With Visual Basic 6

Learn To Program Databases With Visual Basic 6
Muska and Lipman
1929-685-173
Errata and FAQ's
(Last Updated November 22, 2003)

Errata list

Every author endeavors for perfection. My apologies for the typos that have slipped through. We'll do our best to have these corrected for the next printing.

General #1---Unexpected Error--call John Smiley

This happens when you copy the completed China Shop Project (either the one on the CD or one you downloaded somewhere) to your hard drive and try to run it. The reason for that is that the program is 'hard coded' to run from only one location (you'll learn how to fix this in the Objects book using the Path property of the App object).

At any rate, the program can only run from this location

C:\VBFILES\CHINA

so make sure you copy the files there. Any other location will cause this problem. And after you copy the files, make sure they are NOT marked Read-only--something that happens when you copy from a CD.

General #2--Where is the DBGrid32.OCX?

Not an errata, but a potential problem for some readers.

The DBGrid32.OCX that I use in the book for demos is not automatically installed for VB6 Pro and Enterprise versions, and is non-existent on VB6
Learning Edition and Working Model Editions.

For those of you with Pro and Enterprise, here's what you need to do to get the control in your Toolbox

1. Find DBGRID32.OCX somewhere on your installation CD-ROM.
2. Copy it to \Windows\System
3. Find VBCTRLS.REG somewhere on your installation CD-ROM.
4. Copy it to \Windows\System
5. Use Windows Explorer and double click on VBCTRLS.REG---that will register DBGRID32.OCX. You should now see the control when you select

Project-Components

6. Select it to add it to your Toolbox.
7. .Click on the "Browse..." button.
8. Locate the control DBGRID32.OCX
9. Double Click to add it to Project-Components.

For those of you with Working Model and the Learning Edition, here's what you need to do to get the control in your Toolbox (this method courtesy of Bob Stallings---I hope it works for you!)

1. Go to http://www.microsoft.com
2. Click on Customer Sites/ Developer
3. Select Visual Studio
4. Select Samples & Downloads/ Product Updates
5. Select Visual Basic Updates
6. Download vbc.exe (this file will be needed to fix "Licenses Info error message" displayed when running the following file.)
7. Download True Data-Bound Grid (DBGrid)Control.
8. Installing the above should give you access to the DBGrid Component as needed.

General #3---Last Updated Property doesn't work

In the book I cite the LastUpdated Property of the Recordset as a way to determine the date and time that a Table type Recordset was last updated.

In reality, this returns the Date and Time that the Table was structurally modified. My apologies.

To obtain the date and time that a Table was last updated, use this code

MsgBox "Table last updated on " & FileDateTime(App.Path & "\test.mdb")

For more info on the various types of DAO Recordsets, see this Microsoft knowledgebase article on

Recordset Differences

General #4--Error Handler in original China Shop code

There's a bug in the Error Handler for the load procedure of the main form.

If the PRICES.TXT file is not found, we detect it properly, but we wind up generating a cascading form load event. To correct that, you need to follow these steps in the Load Event Procedure of the Main form.

After executing the line of code reading 'Unload frmMain' we should also execute the 'End' statement. Like this:

Unload frmMain
End
Exit Sub

General #5---Can't update program

Not an errata, but ...

If you copy the sample files from the enclosed CD-ROM to your hard drive, most likely they will be marked read-only.

When you try to access the China Database, you'll receive an error message that reads

The Microsoft Jet database engine cannot open the file "C:\VBFiles\China\China.mdb".
It is already opened exclusively by another user, or you need permission to view its data."

To fix this, all you need to do is open up the Windows Explorer, select the China Shop Database, then right click your mouse to bring up the Properties
Window. Un-check the read-only attribute, and you should be fine.

General #6---Access 2000 issues

Not an errata, but ...

If you try to connect to an Access 2000 Database via Visual Basic, you're going to have some problems.

Service Pack 4 (and 5) for VB6 corrects this error.

You can download Service Pack 5 from

http://msdn.microsoft.com/vstudio/downloads/updates/sp/vs6/sp5/default.asp

One word of caution. If you start a project with the Data Control, then download and install the Service Pack, you will need to delete the Data Control then add it back in order to see the changes.

Chapter 1

None that we know of

Chapter 2

Page 61, fourth paragraph. "...the total number of records i the table" should be "...the total number of records in the table".
Page 61, third paragraph from the bottom. "..the record pointer i in the first column" should be "...the record pointer is in the first column"
Page 73,Paragraph 9, Last sentence - "... I had find it on my Student ID card" Should be "... I had to find it on my Student ID card"
Page 78, Third paragraph. "...allows us to use to primary keys from separate tables..." Should be "...allows us to use two primary keys from separate tables..."
Page 82, Last Paragraph, 2nd sentence - "A this point" Should be "At this point"
Page 91, Last Paragraph, 2nd sentence from the end - "... - this is reminder ..." should be "... - this is a reminder ..."

Chapter 3

Page 110. Prices in illustration table at the top of page 110 do not match prices in the inventory table on page 109. Instead of 10, 10 and 40, they should be 25, 5 and 50.
Page 129, Step 9. The Field Size of FirstName really should be 20.
Page 133. The screenshot should be of the completed Design View window for the Inventory table--instead, it is of the Database Window.
Page 143, Step 8. "select the OK button" should be "select the Create button"

Chapter 4

Page 195, last paragraph, first line at the end the "t" is missing from the word "abou". It reads "When we talk abou" and should read "When we talk about".
Page 215, The Demonstration on preventing the deletion of a record. The record is deleted anyway. Modify to code to look like this...

Save = False

Action = vbDataActionCancel
Page 219, line 3. "...that Joe Bullina has agreed with us" should be "...that Joe Bullina has asked us for..."
Page 225, the screen shot at the top of page. The Data Control should have the caption "Data1". The caption is not changed until page 232 when it becomes "Users".
Page 229, third paragraph from the bottom of the page. "This will make your program will run faster". Should be "This will make your program run faster"
Page 219, line 3. "...that Joe Bullina has agreed with us" should be "...that Joe Bullina has asked us for..."
Page 225, the screen shot at the top of page. The Data Control should have the caption "Data1". The caption is not changed until page 232 when it becomes "Users".
Page 229, third paragraph from the bottom of the page. "This will make your program will run faster". Should be "This will make your program run faster"

Chapter 5

Page 245. Recordset Properties table, RecordCount row, Comments column. "For a Dynaset or recordset, ..." should read "For a Dynaset or Snapshot, ...".
Page 259, paragraph 1. This procedure does not work as stated. Having moved the scrollbar, you must click a record in the scrolled list to reset the current record to one in view in the grid. Otherwise, the procedure actually reports the current record before you scrolled.
Page 272, demo. Does not work---please do not attempt to duplicate. Please see General #3 above.

Chapter 6

Page 304, end of Paragraph 5. "An event is something that which happens..." should be "An event is something that happens"
Page 323, Midway through the page. "ISBN, by the way, is defined as a number in the Titles table." should be "ISBN is defined as text in the Titles table."
Page 330, Statement 3 should read "Ensure that you have two apostrophes at the end of the statment."
Page 332, code at top of page. First line either needs a line continuation character or the twisted arrow symbol.
Page 347, lines 7 and 8. "you can see Access that generated one itself" should read "you can see that Access generated that semicolon itself"

Chapter 7

Page 375, The Au_Id field in the screen shot should read '16101'
Page 400, the screenshot. The data control's caption is wrong - it should read "Users".

Chapter 8

Page 432, the Code sample in middle of page: mnuInventory_Click should be mnuUsers_Click
Page 450, Step 28 and 29 both have the Cancel Property set to True. You can only have one command button with the Cancel Property Set to True. The cmdExit Default Property, not Cancel Property, should be set to True.
Page 452. The code for the datCustomers_Reposition() event procedure needs to have a continuation after the “&” at the end of the line datCustomers.Caption = “Users record “ & or a new line arrow because you get a compile error without it.
Page 462, first paragraph, first line. "using sing the DBGrid" should be "using the DBGrid"
Page 478, Step 9. The Price field should come from the Transactions table, not the Inventory table. Price is intended to be a historical price--not the current price of the item.
Page 495, top screenshot. The menu reads View/Update Inventory but the screen pointed to is View/Update Customers

Chapter 9

Page 510 and Page 517. The code for the varResult = needs to have a continuation after the “&” at the end of the line varResult = Msgbox (“Are you “ & or a new line arrow because you get a compile error without it. The same is true for the next line datCustomers.Recordset.Fields(“FirstName”) &.
Page 511. Add this line to the cmdCancel Click Event Procedure.

g_intCustomerNumber = 0

Page 534, Step 12: Add a colon after Cit&y for the Caption property

Chapter 10

Page 577, Step 5. The function header should read: Public Function PriceLookUp(Brand, Item) As Currency
Page 583, last paragraph. "...In this version of the program, we don't need to access the values in those variables from procedures on this from, so ..." should read "...In this version of the program, we don't need to access the values in those variables from procedures on this form, so ..."
On pages 595/596 - The code should read ItemIdLookUp not ItemIDLookUp, provided you properly named it on Page 591. Either way, it won't hurt things--- VB will change the code to look like the Procedure header--however you name it.
Page 609 and Page 613. The else clause of the If objChk.Tag <> “Platter” statement currently reads 'Printer.Print Tab(20); “1”; it should read 'Printer.Print Tab(20); “ 1”;'. Notice the leading space before the 1. This change causes the 1 to lineup with the rest of the numbers in the quantity column.
Page 613, line 5. "...similarly to some of the ..." should be "...similar to some of the ...."
Page 614. The Sales Receipt does not indicate a Complete Place Setting discount is in effect. Modify the code on Page 614 in PrintSalesReceipt to look like this..."

Printer.Print "The total price of your order is ";
Printer.Print Format(m_curTotalPrice, "currency");
If chkChinaItem(0).Value = 1 And _
   chkChinaItem(1).Value = 1 And _
   chkChinaItem(2).Value = 1 And _
   chkChinaItem(3).Value = 1 And _
   chkChinaItem(4).Value = 1 Then
   Printer.Print ". (Price includes a Complete Place Setting Discount) "
End If
Printer.Print
Printer.Print "Thank you for your business!"

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