Inheritance type

InheritanceType.SINGLE_TABLE

Pros

• Simplest to implement and typically offers the best performance for polymorphic queries.
• No join operations needed when querying the base class.
• Easy to add new subclasses without schema changes.

Cons

• All columns for all subclasses are in one table, which can lead to many nullable columns.
• The table can become very wide if there are many subclasses or attributes.
• Potential for wasted space in the database.

InheritanceType.TABLE_PER_CLASS

Pros

• Each entity has its own table, which can be more intuitive.
• Easy to add new attributes to subclasses without affecting other classes.
• Good for cases where subclasses have many unique attributes.

Cons

• Polymorphic queries can be inefficient, often requiring UNION operations.
• Redundant storage of common attributes across tables.
• Not well supported by all JPA providers.

InheritanceType.JOINED

Pros

• Normalized database design with minimal data redundancy.
• Flexible for adding new subclasses or attributes.
• Good balance between normalization and performance.

Cons

• Requires joins for polymorphic queries, which can impact performance.
• Inserts and updates may affect multiple tables.
• More complex queries compared to SINGLE_TABLE.

General consideration

• SINGLE_TABLE is often the default choice due to its simplicity and performance.
• JOINED is a good choice when you need a more normalized database structure.
• TABLE_PER_CLASS can be useful in specific scenarios but is often avoided due to performance concerns with polymorphic queries.
• The choice often depends on your specific use case, the number of subclasses, how often you perform polymorphic queries, and your database design preferences.