The Advanced SQL Engine does not support all the features that are provided by the Entity Framework. When possible, the Entity Provider for Teradata will throw a NotSupportedException when it detects an item in the information sent from the Entity Framework is not supported by the SQL Engine. Scenarios where the Entity Provider will throw a NotSupportedException are discussed below.
There are scenarios where the Entity Framework will generate a SQL statement not supported by the SQL Engine. In these situations, a TdException is thrown. These scenarios are also discussed in the following sections.
In the discussions of the limitations, examples will be given on what causes these exceptions to be thrown. Unfortunately, how the LINQ to Entity and Entity SQL statements are written are based on the Entity Data Model. The SQL statements that are generated by the Entity Provider are also affected by the Entity Data Model. So there may not be a clear concise example that demonstrates a pattern in a LINQ to Entities or Entity Sql statement that will cause an exception to be thrown.
The examples that describe each limitation are based on the Entity Data Model shown in the Querying Data Model Entities.
APPLY Operator Is Not Supported
LOB's Cannot be Specified in Set Operations
Sub-Query in Columns-List of SELECT Statement Is Not Supported In Teradata Version Prior to 13.0
Period Types Are Not Supported In Teradata Releases Prior to 13.0
Teradata Does Not Support A Correlation In a Derived Table Outside Its Scope
Restrictions Using the Current Session Character Set