http://support.microsoft.com/default.aspx?scid=kb;en-us;320435
The following table lists the most common data types that are used in Microsoft Access and how these data types relate to the Microsoft .NET Framework data types and to the OleDbType enumeration.
| Access Type Name | Database Data Type | OLE DB Type | .NET Framework Type | Member Name |
| Text | VarWChar | DBTYPE_WSTR | System.String | OleDbType.VarWChar |
| Memo | LongVarWChar | DBTYPE_WSTR | System.String | OleDbType.LongVarWChar |
| Number: Byte | UnsignedTinyInt | DBTYPE_UI1 | System.Byte | OleDbType.UnsignedTinyInt |
| Yes/No | Boolean | DBTYPE_BOOL | System.Boolean | OleDbType.Boolean |
| Date/Time | DateTime | DBTYPE_DATE | System.DateTime | OleDbType.Date |
| Currency | Decimal | DBTYPE_NUMERIC | System.Decimal | OleDbType.Numeric |
| Number: Decimal | Decimal | DBTYPE_NUMERIC | System.Decimal | OleDbType.Numeric |
| Number: Double | Double | DBTYPE_R8 | System.Double | OleDbType.Double |
| Autonumber (Replication ID) | GUID | DBTYPE_GUID | System.Guid | OleDbType.Guid |
| Number: (Replication ID) | GUID | DBTYPE_GUID | System.Guid | OleDbType.Guid |
| Autonumber (Long Integer) | Integer | DBTYPE_I4 | System.Int32 | OleDbType.Integer |
| Number: (Long Integer) | Integer | DBTYPE_I4 | System.Int32 | OleDbType.Integer |
| OLE Object | LongVarBinary | DBTYPE_BYTES | Array of System.Byte | OleDbType.LongVarBinary |
| Number: Single | Single | DBTYPE_R4 | System.Single | OleDbType.Single |
| Number: Integer | SmallInt | DBTYPE_I2 | System.Int16 | OleDbType.SmallInt |
| Binary | VarBinary* | DBTYPE_BYTES | Array of System.Byte | OleDbType.Binary |
| Hyperlink | VarWChar | DBTYPE_WSTR | System.String | OleDbType.VarWChar |