How Regular @ElementCollection (Without @OrderColumn) Works

Description: This application reveals the possible performance penalties of using @ElementCollection. In this case, without @OrderColumn. As you can see in the next item (34) adding @OrderColumn can mitigate some performance penalties.

Key points:

• an @ElementCollection doesn't have a primary key
• an @ElementCollection is mapped in a separate table
• avoid @ElementCollection when you have a lot of inserts/deletes on this collection; inserts/deletes will cause Hibernate to delete all the existing table rows, process the collection in-memory, and re-insert the remaining table rows to mirror the collection from memory
• the more entries we have in this collection the greater the performance penalty will be

Output example:

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