Read/Write MaxLength and AllowDBNull in System.Data.DataColumn with Access

microsoft.public.dotnet.framework.adonet

15 Dec 2006 3:09 PM

Giorgio

Hi,
I've an Access db and I'm using the following provider:
PROVIDER=Microsoft.Jet.OLEDB.4.0

I need to make an administration tool to create and change table properties,
so I need to read MaxLength and AllowDBNull properties from
System.Data.DataColumn. To do so, I try to get a DataTable in the following
way (DBConnection is an instance of System.Data.OleDb.OleDbConnection):

IDbDataAdapter adapter = new OleDbDataAdapter();
adapter.SelectCommand = DBConnection.CreateCommand();
adapter.SelectCommand.CommandType = CommandType.Text;
adapter.SelectCommand.CommandText = SqlQuery;
DataSet dset = new DataSet();
adapter.Fill(dset);
dset.AcceptChanges();
DataTable retTable = dset.Tables[0];

Now, retTable contains the property Columns but Columns contain only few
properties (e.g. ColumnName and Caption but they don't contain the correct
value of MaxLength and AllowDBNull: MaxLenght is always -1 and AllowDBNull
always true).

Is there a way to read this info? If so, I prefer a database-independent
solution.

Thank you

Giorgio