關系型數據持久化組件：Empire-db

Apache Empire-db 是一個開源的關系型數據持久化組件，能夠實現數據庫無關的動態查詢定義，簡便的數據讀取和更新。與其它持久化組件相比 如：Hibernate、TopLink、iBATIS或JPA實現，Empire-db更注重編譯期類型安全，減少冗余，開發效率的改進。 Empire-db所有的數據庫實體都通過動態bean進行管理，因此允許在運行期改變數據模型。

特性列表：

• No XML schemas or annotations to learn – everything's in Java (Plain Old Java Code).
• Zero configuration footprint - not even one single configuration file!
• DBMS independent data model definition, record handling and command definition, which keeps code portable to all SQL databases.
• Metadata accessible and extensible through standard Java code.
• Type-safe API for dynamic SQL command generation lets you build virtually any SQL statement exactly as you want it; intuitive and completely string-free.
• No need to always work with full database entities. Build queries to provide you with the data exactly as you need it, and obtain the result for example as a list of any type of POJO with matching property setters or constructor.
• Query results or record data may alternatively be obtained as XML even with added metadata.
• Works with dynamic beans and type-safe field access. Special support for data exchange to and from traditional JavaBeans / POJOs is provided.
• Automatic tracking of record state and field modification (aka "dirty checking") to only insert/ update modified fields.
• Support for optimistic locking through timestamp column.
• DDL generation for target DBMS from object definition, either for the entire database or for individual objects such as tables, views, columns and relations.
• Support for data model changes (DDL) at runtime with full dynamic bean support.

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