Natec Systems - PDB Database Classes

PDB Database Classes

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Revision Log:

02/14/05 - Fixed Bug in UniCode to handle more all UniCode Blocks.

02/14/05 - Fixed Bug in ReadNextModified that ignored first record in the database

03/10/04 - UniCode support on strings. Handles a UTF-8 encoding and coding automatically

03/10/04 - Global ByteSwap flag to handle 68000 series byte format. Palm VFS storage.

03/10/04 - Fixed 3 Compile errors in classes

These Classes will allow you to write PDB databases without using Appforge components. These classes are VB6 and are designed to work with desktop applications.

Here is an example:

Dim oPDB As New PDBDatabase
Dim oByteStream As New PDBByteStream
Dim oAppForgeHeader As New PDBAppforgeDefinition
Dim oAppForgeData As New PDBAppforgeRecord

' Creates a new database
If oPDB.CreateDatabase() Then
    ' Successful
    oPDB.PDBDatabaseName = "test"
    oPDB.CreatorId = "TEST"
    
    ' Creates the Appforge header
    oAppForgeHeader.AddFieldName "Test", eStringField
     
    ' Writes a Record
    Set oAppForgeData.AppforgeDefinition = oAppForgeHeader
    oAppForgeData.StringValue(1) = "test"
        
    ' writes the record
    Set oByteStream = oAppForgeData.ByteStream
    oPDB.Update -1, 0, 0, 0, oByteStream.ByteArray
        
    ' Saves the data
    oPDB.WriteAppInfoBlock oAppForgeHeader.AppInfoBlock
    oPDB.CloseDatabase
Else
    ' failed
    MsgBox "Failed to create"
End If

' Changes information in a database
oPDB.PDBDatabaseName = "AFSampleTable"
If oPDB.OpenDatabase Then
    ' Gets the Appforge file infor
    Set oAppForgeHeader = New PDBAppforgeDefinition
    If oAppForgeHeader.IsAppforgeData(oPDB.ReadAppInfoBlock) Then
        ' This is an appforge database.  Setup the Appforge header
        ' information
        Set oAppForgeData.AppforgeDefinition = oAppForgeHeader
        
        ' Updates the appforge data
        Set oByteStream = New PDBByteStream
        oByteStream.ByteArray = oPDB.ReadNextByIndex(1, 0, 0, 0)
        Set oAppForgeData.ByteStream = oByteStream

        Debug.Print oAppForgeData.BooleanValue(1) & " = True"
        Debug.Print oAppForgeData.ByteValue(2) & " = 10"
        Debug.Print oAppForgeData.CurrencyValue(3) & " = 55"
        Debug.Print oAppForgeData.DateValue(4) & " = 1/31/2002"
        Debug.Print oAppForgeData.SingleValue(5) & " = 1.3"
        Debug.Print oAppForgeData.DoubleValue(6) & " = .5544332211"
        Debug.Print oAppForgeData.IntegerValue(7) & " = 340"
        Debug.Print oAppForgeData.LongValue(8) & " = 45300"
        Debug.Print oAppForgeData.StringValue(9) & " = Hello"

        oAppForgeData.StringValue(9) = "test"

        ' writes the record
        Set oByteStream = oAppForgeData.ByteStream
        oPDB.Update 1, 0, 0, 0, oByteStream.ByteArray
   Else
        ' Not Appforge
        MsgBox "Not an Appforge Database"
   End If

   ' Save changes
   oPDB.WriteAppInfoBlock oAppForgeHeader.AppInfoBlock
   oPDB.CloseDatabase
Else
   MsgBox "Failed to open " & oPDB.PDBDatabaseName
End If

The zip file you receive will include a sample form and all class with source code for creating PDB databases.