Why has simple become difficult?

Question

I have two identical databases one in Microsoft Access the other in SQL Server Compact Edition 3.5. Both are OLEDB compliant.
The application I'm writing is designed to be a standalone tool, and changes made to the .NET framework made using Access as a backend data storage no longer practical.
I remade the Access database as a SQL Server Compact Edition 3.5 database using the VB.NET IDE. To save the previous work I changed the Access data provider to the SSCE 3.5 data provider and matched the correct database to the appropriate data provider.
Access Connection String:
Provider=Microsoft.ACE.OLEDB.12.0;Data Source="C:\Users\Mark\Documents\Visual Studio 2008\Projects\BindingCtrls\BindingCtrls\bin\Debug\objBkUp.ACCDB";Persist Security Info=False
SSCE Connection String:
Provider=Microsoft.SQLSERVER.CE.OLEDB.3.5;Data Source="C:\Users\Mark\Documents\Visual Studio 2008\Projects\BindingCtrls\BindingCtrls\bin\Debug\Archives.SDF";Persist Security Info=False
The previously working code failed. I suspected a subtle difference between the databases. A developer acquaintance suggested I write both database schemas into XML files and compare them with a freeware text comparator named 
ExamDiff. In the interest of saving space I'm only going to show one column's differences between the two databases.
Access DB column:
<xs:element name="PCID" type="xs:int" minOccurs="0" />
SQL Server CE column:
<xs:element name="PCID" msdata:ReadOnly="true" type="xs:int" minOccurs="0" />
As you can see the only difference between the two columns is: msdata:ReadOnly="true".
The simple question is: Why can't I change the msdata:ReadOnly="true" property to false using the VB.NET Server Explorer tool inside the VB.NET IDE?
They are suppose to be compatible. There is a flaw.
MRM256

Answer 1

I thought it would be helpful  for those who are interested to place the test application out on OneDrive http://1drv.ms/1hIMEPw , so you can see exactly what I'm doing.
We will test the Access database, followed by the SQL Server CE database. All we are doing is activating one database, add two items; then do the same test with the other database.
In the tests I ran the Access database worked without any problem. However, the SQL Server CE one blew up.
In the frmBinding_Load event I have a section I partitioned off with dashes.
'Function to build Connection string to Access DB
'cnnAccessCtrlDB = objDBCnn.cnnOLDEB(strAppPath & "\objBkUp.ACCDB")
'strDBInUse = strAppPath & "\objBkUp.ACCDB"
'Fill DataSet; including all DataTables and data
'dsAccess = objDBStuff.getDataSetAndFill(cnnAccessCtrlDB)
'Function to build connection to SSCE DB
'cnnSSCE = objDBCnn.cnnOLDEB(strAppPath & "\Archives.SDF")
'strDBInUse = strAppPath & "\Archive.SDF"
'Fill DataSet; including all DataTables and data
'dsAccess = objDBStuff.getDataSetAndFill(cnnSSCE)
For the first test we will active the Access database.
'Function to build Connection string to Access DB
cnnAccessCtrlDB = objDBCnn.cnnOLDEB(strAppPath &
"\objBkUp.ACCDB")
strDBInUse = strAppPath &
"\objBkUp.ACCDB"
'Fill DataSet; including all DataTables and data
dsAccess = objDBStuff.getDataSetAndFill(cnnAccessCtrlDB)
'Function to build connection to SSCE DB
'cnnSSCE = objDBCnn.cnnOLDEB(strAppPath & "\Archives.SDF")
'strDBInUse = strAppPath & "\Archive.SDF"
'Fill DataSet; including all DataTables and data
'dsAccess = objDBStuff.getDataSetAndFill(cnnSSCE)
Press F5 to run the application. Press the Yes button to authorize item archiving on the PC where you are testing this application. Your PC will be different from mine.
Once the form is up on the tree view control open up some folder and add at least two items to the database. Similar to the image below:
As mentioned previously this one works. Now we are going to activate the SQL Server CE database like so:
'Function to build Connection string to Access DB
'cnnAccessCtrlDB = objDBCnn.cnnOLDEB(strAppPath & "\objBkUp.ACCDB")
'strDBInUse = strAppPath & "\objBkUp.ACCDB"
'Fill DataSet; including all DataTables and data
'dsAccess = objDBStuff.getDataSetAndFill(cnnAccessCtrlDB)
'Function to build connection to SSCE DB
cnnSSCE = objDBCnn.cnnOLDEB(strAppPath &
"\Archives.SDF")
strDBInUse = strAppPath &
"\Archive.SDF"
'Fill DataSet; including all DataTables and data
dsAccess = objDBStuff.getDataSetAndFill(cnnSSCE)
Follow the same steps you did to run the application. When you add one item this occurs:
First off you notice five of the six bound controls are empty, but it says one records has been added to the data set table. Select another item and press the plus button on the navigator control.
An invalid casting exception gets thrown: "Cannot cast DBNull.Value to type System.Int32. Please use a nullable type."
This bothers me, because according to Microsoft both of these databases are OLEDB compliant and should function exactly alike.
I would be interested in what will happen on newer versions of Visual Studio.
Thank you,
MRM256