FIX: Jet Provider Errors When Setting a Field Equal to a Field Containing an Empty String (239781)

MORE INFORMATION

Steps to Reproduce Behavior

1. Start a new Standard EXE project. Form1 is added by default.
2. From the Project menu, click References, and select the Microsoft ActiveX Data Objects and Microsoft ADO EXT. for DDL and Security.
3. Place a CommandButton on the form, Command1.
4. Place the following code into Form1:

       Private Sub Command1_Click()
           Dim TheConn As New ADODB.Connection
           Dim TheCat As New ADOX.Catalog
           Dim TheCursor As New ADODB.Recordset
           Dim TheCursor2 As New ADODB.Recordset
           Dim Tbl As New ADOX.Table
           Const sDBName = "c:\test.mdb"
   
           ' Create new database, with two similar tables MyTable and MyTable2
           On Error Resume Next
           Kill sDBName
           On Error GoTo 0
   
           TheCat.Create "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + sDBName
           Tbl.Name = "MyTable"
           Tbl.Columns.Append "Field1", adVarWChar, 20
           Tbl.Columns.Append "id", adInteger
           TheCat.Tables.Append Tbl
           TheCat.Tables("MyTable").Columns("Field1").Properties("JET OLEDB:Allow Zero Length") = True
           Set Tbl = New Table
           Tbl.Name = "MyTable2"
           Tbl.Columns.Append "Field1", adVarWChar, 20
           Tbl.Columns.Append "id", adInteger
           TheCat.Tables.Append Tbl
           TheCat.Tables("MyTable2").Columns("Field1").Properties("JET OLEDB:Allow Zero Length") = True
           TheConn.CursorLocation = adUseClient
           TheConn.Provider = "Microsoft.Jet.OLEDB.4.0"
           TheConn.Open sDBName
           TheConn.Execute "INSERT INTO MyTable (ID, Field1) VALUES (1, '')"
           TheConn.Execute "INSERT INTO MyTable2 (ID, Field1) VALUES (2, 'fred')"
           TheCursor.Open "SELECT * From MyTable WHERE ID = 1", TheConn, adOpenStatic, adLockReadOnly, adCmdText
           TheCursor2.Open "SELECT * From MyTable2 WHERE ID = 2", TheConn, adOpenDynamic, adLockPessimistic, adCmdText
           TheCursor2("Field1") = TheCursor("Field1") ' get error here        'comment the above line and uncomment the line below to eliminate this error 
           'TheCursor2("Field1").value = TheCursor("Field1").value ' get error here
           TheCursor2.Update
       End Sub
   					

5. Run the project and click Command1.