Objective 4.5: State benefits and costs of Container Managed Persistence

Entity Beans can be configured to either use Container Managed Persistence or Bean Managed Persistence.

Container Managed Persistence

Benefits:

• Requires less code (faster development)
• Portable accross database vendor and schema changes
• The container may offer caching services. Therefore, the generated code might be more efficient, especially for the finder methods

Costs:

• Does not suppert (yet) difficult relationships and object types
• Is not necessarily performant (although this might change when CMP becomes more mature)

Bean Managed Persistence

Benefits:

• Offers more control over persistency, as you write the SQL yourself
• With proper constructed SQL, BMP makes a more efficient use of the database
• Can be used with EJB 1.1 container (don't try to use CMP with a container less than 2.0)
• Faster when it comes to complex relationships and datatypes

Costs:

• Needs an extra DAO layer to avoid coupling with a specific database
• Hard to maintain, as all SQL is self written
• Requires more coding