Am not that good yet with spring. Before now I thought its unprofessional to build an application with spring without using hibernate ORM. Until yesterday when I spent a full day trying to execute a "ManyToOne" mapping. Then I came across some threads where I got to know that u should only use hibernate with spring if only u need ORM in your application. That jdbc template will suffice should you not need ORM. Now my question is do I still need relational mapping to execute JOINS in SPRING using JDBC TEMPLATE(without using hibernate at all)
Spring JdbcTemplate allows you deal with native Java driver to work with databases, writing less code than using it directly. As you have guessed, it is a good option when the performance is more important than build a robust application using the "easy way" that brings you an ORM like Hibernate for example.
Answering your question, if you are talking about the Hibernate annotations like #ManyToOne or similar, the answer is no. Using JdbcTemplate you won't need them. However, you will need to specify in every query what are the required columns of every table and the columns of the related ones that you will want to get.
The following links give you some examples about how to deal with JdbcTemplate and joins:
Example 1
Example 2
More information about JdbcTemplate here
Related
I have a Oracle procedure with some 2000 lines with lots of inserts , updates , joins , selects , lot of "insert into select from with multiple and complex joins" I wanted to convert it into java batch. I have multiple options with me to get this done.
Plain JDBC
Spring JDBC template
Hibernate
Spring JPA
I am able to convert the procedure to JAVA using simple plain JDBC and it is working perfectly fine. I optimized the code and it is looking okay. But I would like to consider other alternatives maybe like using Hibernate or JDBC template. Just need suggestions , comments on re-writing it on hibernate. Do you suggest to let it be in plain JDBC or pick any ORM framework ?
Advantages or Disadvantages of picking Hibernate or JDBCtemplate?
Is Hibernate good for complex joins and "insert into select from"??
There is no yes/no answers for these questions. Would like to suggest this link for your analysis:
Spring-JDBC-JPA vs Hibernate
This is about analyzing whether the relational model can be represented in an OO model if you are using an ORM like Hibernate without inducing complexity. If the relational model is complex would like to suggest to use Spring JDBC with native SQL. Spring JDBC handles the boiler-plate issues like opening/closing DB connections,exception handling etc., which needs to be handled by you in the plain old JDBC world.
If you need control on the SQL, since you have mentioned complex joins would be better off writing native SQL. If you are really sure the relational model is properly translated to a robust OO model and you are confident with the SQLs generated by hibernate are optimized based on your foreign-key mappings, then go for hibernate. Of course, there are many convenient features in Hibernate which would not be available in other ORMs. Again, it's about where you want to shift the control, to the developer or the framework. These are my humble suggestions.
Please correct if I have missed out anything.
I haven't worked on JPA so may be other developer experts can comment on that.
I am writing a java application in which I am using Spring Boot and JPA in order to map classes to my database tables.
However, due to a somewhat complex database structure I also have the need of creating custom queries that are not mapped to any specific POJOs / Entities.
Therefore I am using PreparedStatement together with a DataSource with #Autowired annotation.
It hit me that using both of these DB Access methods might not be suitable to use together?
So far everything has worked out in my dev environment, but are there any pitfalls that I should look out for when using both of these together or is there a preferred way of doing custom queries when using JPA?
It should be noted that my database calls are fairly short and happen in a stateless manner, so there should hopefully not be any problems with interfering sessions (?)
JPA EntityManager will not know anything about your changes made with PreparedStatement. This will cause issues with JPA built-in caching, maybe with versioning and also with transaction support.
Though you may need to check this question: Is it OK to use both JPA (for normal CRUDs) and JDBC (for batch update & call stored proc) in the same project
Invan's answer makes a clear point.
On the other hand your fine when:
you need complex queries to SHOW data (read only).
you infrequently need to do some batch updates and do a clear cache entityManager.getEntityManagerFactory().getCache().evictAll()
I'm new with Spring and I would like to use Spring Data with Jpa, Maven and Mysql in Eclipse environment. Then I'm going to use Tomcat as application server
I read a lot of tutorial but all of them are different from each other therefore don't understand what I have really to do. At the moment I'm confusing between these technology and DAO/DAL structure
Must I use Hibernate?
I have to use it with java JPA and then I have to add Spring data?
If anyone has an example or a tutorial I thank him.
Official spring data link
For spring-data-jpa,maven,mysql,hibernate,eclipse example tutorial
Hibernate is optional, it depends on your use case what you want to do. Its a ORM for mapping your db tables into java objects and have lot of other features like session caching, second level caching, criteria queries, validation, search/filters etc.
If you are just testing queries to load data you can use spring jpa queries directly, you will find examples in spring-data-jpa link
what we are planning to do is we want a single project but want to use three different frame works to-gather, so is it a good idea or can this is achievable ?
we have already project build up with spring and hibernate but we want to extend it with jdbc template.
please guide on common quetions like
-New Session factory required or not ?
-Can we use pojos with hibernate annotations with jdbc template or we have to create new one ?
-Will this create problem on performance if average is 500 users at a time ?
Thanks in advance.
Using both an ORM and JDBC in the same application is a reasonable thing to do. Hibernate can run native SQL queries so you might consider that as an alternative depending on what you have in mind.
JDBC doesn't use a session factory or entity manager factory comparable to Hibernate. Caching for the JDBC results would have to be handled separately from Hibernate.
The Hibernate/JPA annotations will be irrelevant to JDBC queries, the RowMapper passed into the query controls how pojos get populated. You could re-use your Hibernate entities to be populated by the rowmappers but in practice the reason you use JDBC is to get more focused results with flatter objects and you end up with a separate set of DTOs.
I'm not clear on what you think is going to hurt performance here. JDBC should be an improvement over Hibernate performance-wise, though at the cost of having business-logic spread out in multiple places. The tricky part will probably be setting up the transaction manager so that JDBC and Hibernate use the same transaction, see this question.
Just trying to get my head round Spring and figuring out how I wire up an Oracle connection in xml config file, and now find out I need yet another framework! - Hibernate, this is soooo frustrating as it feels like I'm getting deeper and deeper into more and more frameworks without actually getting what I need done!
I looked at Hibernate and it seems to do similar things to Spring, bearing in mind I just want to do some SQL inserts in Oracle.
I am reluctant and do not have time to learn 2 frameworks - could I get away with just adopting Hibernate for the simple things I need to do?
...could I get away with just adopting Hibernate for the simple things I need to do?
Yes
Hibernate is for ORM ( object relational mapping ) that is, make your objects persistent to a RDBMS.
Spring goes further. It may be used also as a AOP, Dependency Injector, a Web Application and ORM among other things.
So if you only need ORM, just use Hibernate. Time will come when you need Spring, and you will learn it then.
Here's an architectural view of Spring:
And this is Hibernate:
Spring and Hibernate are totally different frameworks for different problems. Spring is a huge framework with many many features, Hibernate is an O/R bridge.
I would recommend using plain old JDBC in your case ('just some SQL inserts in Oracle').
You could get away with using just spring and spring-JDBC integration. Depending on the complexity of your data-access needs it may be more than enough. The spring Object-relation mapping is also worth looking into if you're going to do a lot of data-access.
The nice thing about spring is that it's a very loosely coupled framework. So you can read up on the bits you use, and forget the rest - even in the runtime.
Spring and Hibernate are really intended to do two different things. Spring is first and foremost an inversion-of-control container and configuration subsystem, while Hibernate is a database binding and lazy loading engine. If you don't want to introduce a bunch of new stuff into your code, stick with Spring and roll your own queries or use iBatis to do much simpler database binding.
If all you want is insert sql for oracle I would stick to a simple JDBC library. All you need is a Connection and maybe some ConnectionPool (maybe c3po). Hibernate and the like are too big/too complicated and IMO inferior. Hibernate incorporates JDBC under the hood but in every measurable way is inferior -- harder to use, not faster, and the queries you have to write or not any easier. It is also a testament to their inferiority because HQL also provides a bypass route so you can enter JDBC queries directly. They provide this (I suspect) because for any complex query you simply can't construct it well in HQL.