The data type of a (column) parameter is specific to the .NET Framework data provider. Specifying the type converts the value of the Parameter to the data provider Type before passing the value to the data source. see also: http://msdn.microsoft.com/en-us/library/system.data.dbtype.aspx example: DbType.AnsiString

public virtual DbType DataType { get; }

Public Overridable ReadOnly Property DataType As DbType
	Get