If an Entity contains a property that maps to a Period type, a TdException will be thrown indicating that "Period" is not recognized.
This problem will occur if an EDM was created using a Teradata Database version 13.0 or later. The SSDL of the EDM contains information that is specific to the version of Teradata that was used in the creation of the EDM. If any of the entities contains properties that map to columns that are defined as Period types, information about the Period will be contained in the SSDL. If this EDM is later used to access a version of a Teradata Database that is earlier than 13.0, a TdException will be thrown when LINQ to Entities or Entity Sql statements are written against these entities are executed.
This problem occurs because the Entity Framework will use the information in the SSDL to process any LINQ to Entities or Entity SQL statements used to query against these entities. The information in the SSDL corresponds to information from a 13.0 or greater release of the Advanced SQL Engine. When the Entity Provider for Teradata is passed this information, it uses the mapping information to construct the SQL statement. When this statement are executed against a 12.0 or earlier release of Teradata this problem is encountered.
The pseudo period column is a derived period column which uses two additional Date or Timestamp columns. These columns are used to define the start and end points of the pseudo period. The pseudo period column cannot be used as an argument to stored procedures, macros or functions. There are many other restrictions, but since pseudo period columns may not be part of the projection list, they are not supported in the Entity Provider. Refer to the Teradata Data Types manual for more information on pseudo period types.