Java开发网 - [j2ee]Java Data Object(JDO) FAQ from Sun

Topic: [j2ee]Java Data Object(JDO) FAQ from Sun

1.[j2ee]Java Data Object(JDO) FAQ from Sun

Posted by: tier3
Posted on: 2002-08-30 13:13

http://java.sun.com/products/jdbc/related.html

Relationship of JDO and JavaTM 2 Platform, Enterprise Edition APIs
What is JavaTM Data Objects (JDO)?
Is JDO a better data access alternative than the JDBCTM API?
Will JDO replace the JDBC API?
Who is participating in the development of the JDO technology?
Will JDO be part of the JavaTM 2 Platform?
How will JDO affect the Enterprise JavaBeansTM technology?
How does JDO relate to the binding of ODMG and the Java programming language?
When is the JDO API expected to be published?
Where can I download the JDO specification, reference implementation, and/or technology compatibility kit?
Where can I learn more about JDO?

Q: What is JavaTM Data Objects (JDO)?

A: Java Data Objects (JDO) is an API for transparent database access. The programmer can write code in the Java programming language that transparently accesses the underlying data store, without using database-specific code.

Q: Is JDO a better data access alternative than the JDBCTM API?

A: JDO is a technology that is complementary to the JDBC API. Its main strength is that it standardizes object databases and object/relational mappings for the JavaTM programming language, allowing the programmer to use classes in the Java programming language instead of copying data between different data models.

Q: Will JDO replace the JDBC API?

A: No. The JDO and JDBC APIs are complementary approaches. Both of these technologies have unique strengths and can be used by programmers with different skill sets and different development objectives.

JDO scores higher on programmer convenience, affording compile-time type checking. JDO hides SQL from the programmer; that is, a developer using the Java programming language does not need to learn SQL.

On the other hand, the JDBC API provides greater flexibility by giving programmers direct control over database access and cache management. The JDBC API is a more mature technology, enjoying very broad industry cceptance as a complete and well-understood API.

Q: Who is participating in the development of the JDO technology?

A: The JDO API is being created under the Java Community Process with Craig Russell of Sun Microsystems as spec lead.

Will JDO be part of the Java 2 Platform?

A: JDO is being defined in parallel with the J2EE platform. At this time, JDO has not been included in the next release of the J2EE platform, nor has a definite decision been made to exclude it. It is expected that JDO will follow the lead of the container and connector APIs in the next J2EE release by referring to those APIs, not by defining mechanisms of its own.

Q: How will JDO affect the EJB technology?

A: JDO is a suitable implementation (1) for persistent helper classes for Session Beans, (2) as delegate classes for Bean Managed Persistence Entity Beans, and (3) for delegate classes for Container Managed Persistence Entity Beans.

Q: How does JDO relate to the binding of ODMG and the Java programming language?

A: While there are some similarities between JDO and the ODMG Java binding, JDO is based on a native Java language approach and is not a mapping between the Java programming language and any existing object-oriented data access standard.

Q: When is the JDO API expected to be published?

A: The specification, reference implementation, and technology compatibility kit were approved by the Java Community Proccess SM (JCPSM) in March, 2002 and published in April 2002.

Q: Where can I download the JDO specification, reference implementation, and/or technology compatibility kit?

A: The JDO specification, reference implementation, and technology compatibility kit are available for download off the Sun.com website. See http://access1.sun.com/jdo for more information.

Q: Where can I learn more about JDO?

A: For more information on the JDO specification, see the JSR-12 website and the JDOcentral.com website.