Registered: Jun 2001
Java Data Objects - JDO
Java Data Objects, aka JDO, is an emerging Java technology for object persistence.
Quoting from the JDO Specification:
"There are two major objectives of the JDO architecture: first, to provide application programmers a transparent Java-centric view of persistent information, including enterprise data and locally stored data; and second, to enable pluggable implementations of data stores into application servers."
JDO is in the final stages of the Java Community Process and is referred to as JSR 12.
One big appeal of this standard is for implementers of EJB servers as a facility for providing container-managed persistence of Java objects.
JDO provides a replacement for JDBC, SQLJ and Serializable, all of which are currently in use for object-persistence. The JSR explains the differences between JDO and these technologies:
"Existing specifications for persistence include JDBC, SQLJ, and java.util.Serializable. The JDBC and SQLJ mechanisms provide for query, transactions, and large capacity storage, but require that users learn another language (SQL). This proposal allows users to specify their application program logic, including queries, entirely in Java, and express the mapping, if any, to the database with a separate mechanism. The java.util serialization protocol provides for persistence, but it does not offer query capability, transactional behavior, nor large capacity data storage. In addition, both the serialization and SQL APIs require that the programmer explicitly fetch and store Java objects from a database; we propose transparent persistence, doing this automatically."
You can get a good jump start on JDO by downloading the specification using the link given above.
Last edited by wellington on 11-08-2001 at 03:35 AM
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