1. Systems Development Group Project Programming Access Forms

2. Lab Exercise from Appendix 9 PET OWNER has 1 m Use this to populate the list box on the pet form later.

3. Access Forms 1. Bound Forms 2. Unbound Forms e.g. a Menu Forms are often a mixture of bound and unbound

4. Access Forms Form Detail Right click here to see form properties Some useful form properties

5. Access Forms Control Box Property to turn these on or off Record Selectors property to turn these on or off Min Max Property to turn these on or off Plus various event properties – the LOAD event is especially important

6. Access Forms Naming the controls on your forms Form names start with frm e.g. frmPet, frmMenu Text boxes should start with txt e.g. txtPetNo Combo boxes with cmb e.g. cmbOwner List boxes with lst e.g. lstPetType Button with cmd e.g. cmdExit Naming is VERY important and it’s better not to include spaces in the names. Naming should always be the FIRST thing you do with a new form or control Don’t confuse the caption property with the name property. Caption for a command button (for example) is what is written on the button e.g. OK, MainMenu, etc.

7. Access Forms – Tool Box LabelText Box Command Button List Box Combo Box Subform

8. Access Forms Navigation buttons Subform Form Header Form Footer Text Box Label

9. Access Forms Note multiple associated records Default View property set to ‘Continuous Forms’ NOT ‘Datasheet’ OwnerNo and PetNo have Visible property set to ‘No’ These labels are in the sub- form header Data Entry property is set to ‘No’

10. Access Forms Private Sub cmdExitPet_Click() ‘Not using Wizard ‘closes this form DoCmd.Close ‘opens main menu form DoCmd.OpenForm "frmVetMenu" End Sub Combo Box List Box Code in the On Click event of the Main Menu button (click on the property then on & then on ‘Code Builder’ to open up a code window. …

11. Access Forms Private Sub cmdMainMenu_Click() On Error GoTo Err_cmdMainMenu_Click Dim stDocName As String Dim stLinkCriteria As String stDocName = "frmVetMenu“ DoCmd.OpenForm stDocName,,, stLinkCriteria Exit_cmdMainMenu_Click: Exit Sub Err_cmdMainMenu_Click: MsgBox Err.Description Resume Exit_cmdMainMenu_Click End Sub This the code for the other ‘Main Menu’ button, this time generated by the Wizard. Would need to insert DoCmd.Closeform here. Wizards can make things easier sometimes, but can also make code unnecessarily complicated

12. List and Combo Boxes Important control settings Can build a query for the row source …

13. Next Week Passwords Calculated Fields Adding new values to lists and combos Depending on how much you know about Access and VBA you should be working on the exercise in Appendix 9 as a way of improving your skills. Only start on your main project when you have planned and designed the forms you want in your system and know how to do the programming.

14. Passwords More than one way to do this We will look at A very basic way of adding password protection A more complex (but also more flexible) way Putting a calculated value into a text box on a form

15. Passwords – Easy but Basic Method Open the database in exclusive mode

16. Passwords Then select Tools -> Security > Select Database Password Type the password you want to use. Next time you attempt to open the database file you will be asked to enter the password as shown below: The password can be removed in the same way

17. Passwords It is possible to assign more complex arrangements of users and groups of users with different permission from within the Tools -> Security menus. You would need to investigate this carefully before trying it Also look at Tools -> Start Up. This enables you to switch off menus etc on starting the database. Make a copy of your database file before trying any of this or you may end up not being able to get at any of your work!

18. Using VBA to Set User Ids and Passwords The vet database has an example of this implemented Start by creating a new table:

19. Passwords 1. Create a new form 2. We Can add code to the controls of the form to cause it to check the user ID and Password entered. 3. Use the On Exit property of the UserID text box 4. Use the on click property of the OK button

20. Data Access Objects (DAO) Go into the Code Builder for the On-exit event of the UserID text box Select Tools -> References from the menu Select Microsoft DAO Object Library DeSelect Microsoft ActiveX Data Objects library Enables us to use Record Sets

21. Check UserID Private Sub txtUserID_Exit(Cancel As Integer) Dim dbUsers As Database Dim rsUsers As Recordset Set dbUsers = CurrentDb Set rsUsers = dbUsers.OpenRecordset("Select * from tblUser") rsUsers.FindFirst "UserID='" & txtUserID & "'" If rsUsers.NoMatch Then MsgBox ("Invalid Username") Cancel = True txtUserID = "" 'txtUserID.SetFocus End If rsUsers.Close dbUsers.Close End Sub On Exit property of USERID text box Sets up database and recordset variables Initialises the variables so that rsUsers is a copy of the Users table Finds the first userID in the recordset that matches the userID entered Close the variables – (in this order) If there’s no match… Stops on-exit event

22. Checking Password Private Sub cmdOK_Click() Dim dbUsers As Database Dim rsUsers As Recordset Set dbUsers = CurrentDb Set rsUsers = dbUsers.OpenRecordset("Select * from tblUser") rsUsers.FindFirst "UserID='" & txtUserID & "'" If txtPassword = rsUsers!Password Then DoCmd.Close DoCmd.OpenForm "frmVetMenu" Else MsgBox ("Invalid Password") txtPassword = " " txtPassword.SetFocus End If rsUsers.Close dbUsers.Close End Sub If the password is correct the vet menu is opened If the password is incorrect we get a message and can try again On Click event of the OK button

23. What else can we do with record sets? Various methods are available: FindFirst FindNext FindPrevious MoveNext MovePrevious There is more about this on Tugrul’s Essendal’s web page for the CSCI2010 module: http://www.cse.dmu.ac.uk/~the/csci2010/T&L.htm

24. Record sets Useful for manipulating data via the forms The Record set is a variable that holds the result of an SQL query – the query result can be a whole table, or part of a table etc. E.g. Select * from tblUser Using methods like FindFirst etc. causes a pointer to point at a particular row or record in the recordset

25. Record sets So this code: rsUsers.FindFirst "UserID='" & txtUserID & "'“ Causes the pointer to point at the first row in the recordset (which is holding a copy of tblUser) that has a value for UserID that is the same as that entered in the UserID text box. So if I’d typed Carter as my UserID, find first would point at the 2 nd record

26. Record sets When using record sets you always have to: Declare a database variable Declare recordset variable Dim dbUsers As Database Dim rsUsers As Recordset Then you have to initialise them: Set dbUsers = CurrentDb Set rsUsers = dbUsers.OpenRecordset( "Select * from tblUser“ ) And you have to close them rsUsers.Close dbUsers.Close

27. Different menus for different user types If txtPassword = rsUsers!Password Then If rsUsers!UserType = 1 Then DoCmd.Close DoCmd.OpenForm "frmVetMenu“ Else DoCmd.Close DoCmd.OpenForm “frmOtherMenu” End If Else MsgBox ("Invalid Password") etc. etc Enhancement of code from the OK button on frmUser

28. Calculation example A treatment table has been added to the database, such that:: a pet has many treatments, and a treatment is for 1 pet tblTreatment(TreatmentID, PetNo, Description, Cost) PET TREATMENT has m 1

29. Calculating total cost per pet A text box called txtCost has been added to the Pet form in which we want to see the total cost of all treatments for that pet How? Create a query that selects the list of cost values for the PetNo currently shown on the form: SELECT tblTreatment.Cost FROM tblTreatment WHERE (((tblTreatment.PetNo)=[forms]![frmPet]![txtPetNo])); The SQL view of the query should look like this

30. Calculating cost so far per pet In the on-current event property of the Pet form, enter the following code: txtCost = DSum("[Cost]", "qryTotalCostRows") This adds up (sums) the list of costs in our query and puts it in the txtCost textbox. And to improve the format of the output within the text box: txtCost = FormatCurrency(DSum("[Cost]", "qryTotalCostRows"))

31. Aggregate functions Dsum is an example of an aggregate function You can also use DAvg, DCount, DMin, DMax You can include calculations within these as well: e.g. txtOrderTotal = DSum(“[UnitPrice]*[Quantity]”, “Order_Line”)

32. Finally Download the example database from the web page – the password to get into it initially is jenny Look in the users table to see the usernames and passwords required to enter via the frmUser Log In form Look at the other code on the various forms and make use of it where necessary in your own applications Download copies of these slides from the web The only way to get used to developing Access applications is to put a lot of time into practising. There are two other example databases you can look at on the L drive in the directory CSCI1403 – one on frozen foods, the other on camping equipment – we have been kindly offered the use of these by another member of staff