There is a new bug related to partition keys in the C# driver 2.5 effecting partition keys when using POCOs decorated with attributes for creating column families in Cassandra. This is a regression as the bug did not exist in C# driver version 2.1.5.
When attempting to create the table via the CreateIfNotExists method of the session object, the following error is thrown: "No partition key is defined."
Code is as follows:
Please let me know if you need additional information or documentation.
Using Cassandra 2.1.2 on a Windows 8.1 update development laptop.
It looks like you are using a mix of new mappings and the legacy GetTable<T>() extension method.
In your example, replace the table instance create with: