From the OLEDB Provider Technical Document:

It is still anticipated that some fields will not require date/time conversion, such as date only or time only type fields.  To accomplish this, the SECTABLEDEFs table has a new column named DATETIMETYPE.  This is a single character field that makes the following assumptions:

1. If it contains a "D" or "T" (date only or time only respectively) it indicates to the OLE DB provider that this field does not require UTC conversion, and will therefore be passed through without alteration.
2. "Z" is reserved, is unsupported by third party use, and is not guaranteed to be supported in future versions of SalesLogix.
3. "U" (or any other value) indicates the default, and the date/time field is stored as UTC, and should be converted to the local time on the client machine.

The DB Manager will set these values appropriately when creating or altering tables with date/time fields.  The user can specify a date only, time only or regular date/time field.