Microsoft KB Archive/209871

= ACC2000: How to Create a Password Protected Form or Report =

Article ID: 209871

Article Last Modified on 6/23/2005

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APPLIES TO


 * Microsoft Access 2000 Standard Edition

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This article was previously published under Q209871



Advanced: Requires expert coding, interoperability, and multiuser skills.

This article applies only to a Microsoft Access database (.mdb).



SUMMARY
Microsoft Access has two built-in security features for protecting your database:
 * User/Group accounts and permissions
 * Database passwords

This article shows you how you can also set individual passwords for each form and for each report in your database.



MORE INFORMATION
Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements.

CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.

NOTE: The sample code in this article uses Microsoft Data Access Objects. For this code to run properly, you must reference the Microsoft DAO 3.6 Object Library. To do so, click References on the Tools menu in the Visual Basic Editor, and make sure that the Microsoft DAO 3.6 Object Library check box is selected.

Using Code to Password Protect a Form
By using code, you can prompt for a password when a user opens a form or a report. If the correct password is entered, the form or the report is opened.

The following example shows you how you can password protect the Orders form in the sample database Northwind.mdb:  Start Access and then open the sample database Northwind.mdb. Press ALT+F11 to start the Microsoft Visual Basic editor. On the Insert menu, click Module.  In the module sheet, type the following procedure: Public MyPassword Public Function KeyCode(Password As String) As Long ' This function will produce a unique key for the ' string that is passed in as the Password. Dim I As Integer Dim Hold As Long

For I = 1 To Len(Password) Select Case (Asc(Left(Password, 1)) * I) Mod 4 Case Is = 0 Hold = Hold + (Asc(Mid(Password, I, 1)) * I)     Case Is = 1 Hold = Hold - (Asc(Mid(Password, I, 1)) * I)     Case Is = 2 Hold = Hold + (Asc(Mid(Password, I, 1)) * _           (I - Asc(Mid(Password, I, 1)))) Case Is = 3 Hold = Hold - (Asc(Mid(Password, I, 1)) * _           (I + Len(Password))) End Select Next I  KeyCode = Hold End Function  Press ALT+F11 to return to Access. In the Database window, under Objects, click Tables, and then click New.</li> In the New Table dialog box, double-click Design View.</li>  Create a new table as follows: <pre class="fixed_text">  Table: tblPassword ---  Field Name: ObjectName Data Type: Text Field Size: 50 Field Name: KeyCode Data Type: Text Field Size: 25 Input Mask: Password

Table Properties: tblPassword -     PrimaryKey: ObjectName </li>  Open the tblPassword table and then enter the following data: <pre class="fixed_text">    ObjectName: Orders KeyCode: 2818 </li> Create a new form in design view and save the form as frmPassword.</li> Add a single textbox to frmPassword called Text0, and a command button called CheckPassword.</li> Set the Input Mask property of Text0 to "PASSWORD" (minus the quotation marks).</li>  Add the following code to the OnClick Event of the CheckPassword button and then save the form: If IsNull(Forms!frmPassword!Text0.Value) Then MsgBox "You cannot enter a blank Password. Try again." Me!Text0.SetFocus Else MyPassword = Me!Text0.Value DoCmd.Close acForm, "frmPassword" End If                    </li> Open the Orders form in Design view.</li> If the property sheet is not visible, click Properties on the View menu.</li>  Type the following event procedure in the module for the OnOpen property of the form: Private Sub Form_Open(Cancel as Integer) Dim Hold As Variant Dim tmpKey As Long Dim I As Integer Dim rs As DAO.Recordset Dim db As DAO.Database

On Error GoTo Error_Handler ' Prompt the user for the Password. DoCmd.OpenForm "frmPassword", acNormal,, , , acDialog Hold = MyPassword ' Open the table that contains the password. Set db = CurrentDb Set rs = db.OpenRecordset("tblPassword", dbOpenTable) rs.Index = "PrimaryKey" rs.Seek "=", Me.Name If rs.NoMatch Then MsgBox "Sorry cannot find password information. Try Again" Cancel = -1 Else ' Test to see if the key generated matches the key in     ' the table; if there is not a match, stop the form ' from opening. If Not (rs![keycode] = KeyCode(Cstr(Hold))) Then MsgBox "Sorry you entered the wrong password." & _           "Try again.", vbOKOnly, "Incorrect Password" Cancel = -1 End If  End If   rs.Close db.Close Exit Sub

Error_Handler: MsgBox Err.Description, vbOKOnly, "Error #" & Err.Number Exit Sub End Sub </li> Close and then save the Orders form.</li> Open the Orders form and then type PASSWORD when you are prompted for a password.

Notice that the Orders form opens. The KeyCode that is generated by PASSWORD matches the KeyCode in the tblPassword table, and is dependent on the case of the letters in the password entered.</li> Close and then reopen the Orders form and then type PassWord when you are prompted for a password.

Notice that you receive the message:

Sorry you entered the wrong password. Try again.

The Orders form does not open because the password procedure is case-sensitive.</li>  To determine what the corresponding KeyCode is for a particular string, type the following in the Immediate window and then press ENTER: ?KeyCode("TestString") The earlier example returns 5864. </li> To hide the tblPassword table in the Database window, right-click the tblPassword table, and then click Properties. In the Properties window, click to select the Hidden check box, and then click OK.</li></ol>

Additional query words: password

Keywords: kbhowto KB209871

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