Main reasons for Oracle TopLink Open Source

The main reason why Oracle opened TopLink open source is that it had to do so. If Oracle opened TopLink open source earlier, i'm afraid this may not be the case for the current ORM or the entire persistence domain. Allen: For me, this means that there will be another excellent Provider when using JPA in the future, which is good!

Hantsy: You know, the standard implementation of JPA is Oracle TopLink, which is half a year earlier than Hibernate's implementation of JPA... TopLink started in 1994 and was later acquired by Oracle. It is much more qualified than Hibernate...

Arthur as. Hui: I learned from Sun2Bin that with TopLink, the Java Community standards actually depend on the number of its users, which is good for things and has many qualifications.

I feel that from the perspective of time cost, TopLink is not worth a try. Like Hibernate, TopLink has the same learning curve as Hibernate. I also have a few eyes on TopLink. I think, it is not very easy to master TopLink. In this case, it is better to use Hibernate as Lady of the village.

TopLink is an early product that initially targets C ++ and later implements Java ing. Oracle open TopLink has excellent performance and powerful functions, and provides a unique query filter mechanism, as well as very effective link processing and query. Therefore, topLink gradually wins from commercial O/R Mapping products and becomes the most outstanding ing product in the market. Because of this, Oracle, the largest relational database vendor, acquired it and became the vendor that provides the strongest database and the most powerful object ing middleware.

Although TopLink is powerful, things that are too powerful cannot be forgotten. TopLink begins to lock users to their own products. The query method is the most prominent. Its query system contains many awkward concepts in my opinion), but developers can only accept this to achieve functions that are not available in general O/R products. Slowly, there are also complaints, coupled with the high price, so that many new and old users are discouraged. As a result, free products began to rise.

There are many free O/R Mapping tools. Here we only mention the two most influential tools: Castor and Hibernate.

Castor is a Java-oriented packaging tool developed by Exolab. Its biggest feature is to implement most of the odmg oql specifications, you can use a class chart like an object database for query ). The principle is to set and read attributes through the Java reflection API.

However, for various reasons, the version update of Castor is getting slower and slower, and the final stop is before 1.0, becoming the O/R Mapping product that has not yet reached the official version 1.0. In any case, it is still a pretty good product.

Hibernate is a very popular O/R Mapping product. It is now available in version 2.0. It has the same powerful functionality and uses the Java reflection API to set objects, however, its query language is a unique system, which is a bit similar to Oracle TopLink, but Hibernate is more friendly and easier to query the relationship, but compared with Castor, it is still inferior in terms of convenience and standardization. In terms of the current situation, the user volume and technical support of Hibernate are stronger.

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