December 21, 2014
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Make a Reusable Database Class

  • November 19, 2002
  • By Sam Huggill
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This database class might need you to change one db path setting (which could be improved by using a public variable). Otherwise it contains prettry much the same functions as the previous article apart from the addition of the repair and compact functions.

Add a new class module and rename it cDataFunc. Copy the following code into it:

  
Option Explicit

'Public members of this module
Public iID As Integer
Private db As Database
Private RS As Recordset

Public Sub OpenDB(dbName As String)
   
  'Open the database
  Set db = OpenDatabase(dbName)

End Sub

Function GetNextRecord(sRecordSet As String, sField As String, iPos As Integer) As String

  'Open the recordset and select the next record
  Set RS = db.OpenRecordset("SELECT * FROM " & sRecordSet & " WHERE _  
    " & sField & " =" & iPos, dbOpenDynaset)

  'Return the field value
  iID = "" & RS.Fields(sField).Value

  'Close the recordset
  RS.Close

End Function

Function UpDate(sRecordSet As String, sField As String, _  
  sValue As String, sFieldToUpdate As String, sValueToUpdate As String)

  'Open the Contact table
  Set RS = db.OpenRecordset("SELECT * FROM " & sRecordSet _  
    & " WHERE " & sField & " = " & sValue, dbOpenDynaset)

  With RS

      'Set it in edit more
      .Edit

      'Update the following fields
      .Fields(sFieldToUpdate).Value = sValueToUpdate

      'Update the table
      .UpDate

      'Close it
      .Close
  End With

End Function

Function AddToDatabase(sRecordSet As String,_ 
  sFieldToAdd As String, sValueToUpdate As String)

  'Open the Contact table
  Set RS = db.OpenRecordset("SELECT * FROM" & sRecordSet _ 
    & " Contact", dbOpenDynaset)

  With RS

    'Set it to Add mode
    .AddNew

    'Enter the field values
    .Fields(sFieldToUpdate).Value = sValueToUpdate

    'Update it
    .UpDate

    'Close it
    .Close
  End With

End Function

Function DeleteFromDatabase(sRecordSet As String, _ 
  sField As String, sValue As String)

  'Open the Contact table
  Set RS = db.OpenRecordset("SELECT * FROM"_ 
    & sRecordSet & " WHERE" & sField & " = " & sValue & "'", dbOpenDynaset)

  With RS

    'Set it to delete mode
    .Delete

    'Close it
    .Close
  End With

End Function

Function RepairDatabase(sDBName As String)
  db.Close

  DBEngine.RepairDatabase sDBName

  OpenDB (App.Path & "\demo.mdb")
End Function

Sub CompactDatabase(sDBName As String, sBackup As String)

  db.Close

  'Check to see if the tempory backup exists
  If Len(Dir$(sBackup)) > 0 Then 'Backup exists

    Kill sBackup 'Delete it

  End If

  'Compact the database to the tempory one
  DBEngine.CompactDatabase sDBName, sBackup

  'Delete the current one
  Kill sDBName

  'Compact the backup to the actual database
  DBEngine.CompactDatabase sBackup, sDBName

  'And remove the backup database
  Kill sBackup

  OpenDB (App.Path & "\demo.mdb")

End Sub

Sub BackupDatabase(sDBPath As String, sOutput As String)

  If Len(Dir$(sDBPath)) > 0 Then 'Backup exists
    Kill sDBPath 'Delete it
  End If

  'Output to new database
  DBEngine.CompactDatabase sOutput, sDBName

End Sub

Add a new form (frmTest). To the form add six command buttons (cmdAdd, cmdDelete, cmdCompact, cmdUpdate, cmdNext and cmdRepair.) Add three text boxes and a label (txtName, txtPhone, txtNotes and lblID). Copy the following code into the form's General Declarations procedure:

'Private declarations for the database and recordset
Private db As Database
Private RS As Recordset
Private m_cData As cDataFunc

Private Sub cmdAdd_Click()
  'Set the global variables
  sName = txtName
  sPhone = txtPhone
  sNotes = txtNotes

  'Call the add function
  m_cData.AddToDatabase "Contact", "Name", sName
End Sub

Private Sub cmdCompact_Click()
  m_cData.CompactDatabase App.Path & "\demo.mdb", App.Path & "\backup.mdb"
End Sub

Private Sub cmdDelete_Click()
  'Set the global variables
  sName = txtNamer
  sPhone = txtPhone
  sNotes = txtNotes

  'Call the delete function
  m_cData.DeleteFromDatabase "Contact", "Name", sName
End Sub

Private Sub cmdNext_Click()
  'Call the next record function
  m_cData.GetNextRecord "Contact", "Name", iID
End Sub

Private Sub cmdRepair_Click()
  m_cData.RepairDatabase App.Path & "\demo.mdb"
End Sub

Private Sub cmdUpdate_Click()
  'Set the global variables
  sName = txtName
  sPhone = txtPhone
  sNotes = txtNotes
  iID = lblID

  'Call the Edit function
  Call m_cData.Update("Contact", "PersonID", lblID)
End Sub

Private Sub Form_Load()
  Set m_cData = New cDataFunc
  m_cData.OpenDB (App.Path & "\demo.mdb")
End Sub

Private Sub Form_Unload(Cancel As Integer)
  Set m_cData = Nothing
End Sub

Download the project files (All the code below)






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