Previous conversation (with ChatGPT):
For the Hibernate library, when dealing with polymorphic relationships where Animal is an interface and not a class (whether partially abstract or concrete),

1) would the TABLE_PER_CLASS strategy lead to redundant columns and potential data duplication?

2) would the TABLE_PER_CLASS strategy be inefficient for querying the entire inheritance hierarchy?
1) The TABLE_PER_CLASS strategy in Hibernate creates a separate table for each concrete subclass of the Animal interface. In this strategy, each table will contain only the columns specific to that subclass, along with the columns inherited from the Animal interface. So, there won’t be any redundant columns or data duplication as each table only holds the columns specific to that subclass.

2) In terms of querying the entire inheritance hierarchy, the TABLE_PER_CLASS strategy can be less efficient compared to other strategies like Single Table or Joined Table. When you query the entire hierarchy, Hibernate needs to perform separate queries on each subclass table and then combine the results. This can result in additional overhead and potentially slower performance compared to other strategies. However, the actual performance impact depends on various factors like the number of subclasses, amount of data, and the complexity of the query. It is recommended to benchmark and analyze the specific scenario to determine the impact on performance.
If Animal was a partially abstract class or concrete class, then the answers for both 1 and 2 would differ, right?
Yes, if Animal is a partially abstract class or a concrete class instead of an interface, the answers for both 1 and 2 would differ.

1) Redundant columns and potential data duplication:
In the TABLE_PER_CLASS strategy, if Animal is a partially abstract class or a concrete class, then each subclass table would have the columns specific to that subclass, along with the columns inherited from the Animal class. There won’t be redundant columns or potential data duplication because each table will only store the relevant columns for that particular subclass.

2) Efficiency for querying the entire inheritance hierarchy:
If Animal is a partially abstract class or a concrete class, the TABLE_PER_CLASS strategy can be more efficient for querying the entire inheritance hierarchy compared to when Animal is an interface. With a partially abstract class or a concrete class, Hibernate can perform a single query across all the subclass tables using SQL UNION or other techniques. This can result in better performance compared to querying each subclass table separately. However, as mentioned before, the actual efficiency depends on various factors and it is recommended to benchmark and analyze the specific scenario to determine the impact on performance.
Is your latest 1 incorrect?
Apologies for the confusion in my previous response. You are correct, my previous answer for 1 was incorrect in the context of the TABLE_PER_CLASS strategy.

If the Animal is a partially abstract class or concrete class, then in the TABLE_PER_CLASS strategy, each concrete subclass table will duplicate the common columns inherited from the Animal class. This duplication can potentially lead to redundant columns and data duplication across the tables.

For example, let’s say the Animal class has a property called “name” and two concrete subclasses, Dog and Cat, also have the same property. In this case, the name column would be duplicated in the Dog table and the Cat table.

This duplication of columns can result in potential data redundancy, as any changes made to the common columns in the Animal class would need to be synchronized across all the concrete subclass tables.

In contrast, if Animal were an interface, there would be no columns inherited from Animal, and each concrete subclass table would only contain its specific columns, avoiding data duplication. 

Current conversation:
Is your latest 2 (also) incorrect?