I'm working on a new project, using concepts like clean architecture, protecting my model and business rules from external dependencies and frameworks. Also, I prefer not to use traditional ORM libraries (like JPA/Hibernate) and have choose to use plain jdbc (through spring jdbctemplate).
It was going pretty well, but I'm getting tired of write 20x almost the same query for all my domain classes on a basic crud reposity. So, I take a look at Spring Data JDBC, but it appears that it's necessary to add annotations on my domain classes to make it work properly. I really don't want to do that, first because I want to make my domain cleaner as possible from any dependencies, and second because this is one of the (many) things I really dislike on JPA.
I was wondering that, the repository needs only 2 things: a rowmapper definition and the PK definition (and both could be defined at the repository itself) avoiding the complete use of annotations.
So, my question is there any way to use Spring Data JDBC without annotations?
No, there is no easy way to use Spring Data JDBC (https://spring.io/projects/spring-data-jdbc).
What you could do is to replace those classes that do the annotation interpretation (RelationalPersistentEntityImpl, and BasicRelationalPersistentProperty) and replace them with something that gets the information from elsewhere.
There is a different framework wich might fit the bill which is also named Spring Data JDBC 🤷♀️ https://github.com/nurkiewicz/spring-data-jdbc-repository
It seems pretty close to what you are looking for but it has its last commit 6 years ago and is archived on Github.
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I'm working on a new project, using concepts like clean architecture, protecting my model and business rules from external dependencies and frameworks. Also, I prefer not to use traditional ORM libraries (like JPA/Hibernate) and have choose to use plain jdbc (through spring jdbctemplate).
It was going pretty well, but I'm getting tired of write 20x almost the same query for all my domain classes on a basic crud reposity. So, I take a look at Spring Data JDBC, but it appears that it's necessary to add annotations on my domain classes to make it work properly. I really don't want to do that, first because I want to make my domain cleaner as possible from any dependencies, and second because this is one of the (many) things I really dislike on JPA.
I was wondering that, the repository needs only 2 things: a rowmapper definition and the PK definition (and both could be defined at the repository itself) avoiding the complete use of annotations.
So, my question is there any way to use Spring Data JDBC without annotations?
No, there is no easy way to use Spring Data JDBC (https://spring.io/projects/spring-data-jdbc).
What you could do is to replace those classes that do the annotation interpretation (RelationalPersistentEntityImpl, and BasicRelationalPersistentProperty) and replace them with something that gets the information from elsewhere.
There is a different framework wich might fit the bill which is also named Spring Data JDBC 🤷♀️ https://github.com/nurkiewicz/spring-data-jdbc-repository
It seems pretty close to what you are looking for but it has its last commit 6 years ago and is archived on Github.
I have requirements to let users create their own tables and to create their own forms dynamically inside application. One can image that there can be 3 separate tables: user_relations, user_relation_fields, user_relation_field_values. Together they can satisfy requirements. But apparently such solution is involved, each select requires lot of joins. It is easy to create tables dynamically and it is easy to create CRUD SQL statements dynamically from the set of fields which have been defined by users. I prefer to use annotations (instead of configruation XML files), therefor dynamic update of configuration files may not be necessary.
The question is - how to create ORM (JPA, Spring Repository) mapping to dynamically created tables. Is it possible dynamically create entities and insert them as part of already running application? Is it possible to dynamically create code of facelets pages and insert then in application? Is it good practice.
Lot of ERP type applications allow some kind of flexfields or extensibility features so this should be possible.
I have heard that Grails is dynamic Java with metaprogramming features maybe it is more appropriate to create such application in Grails (especially because it uses Spring and Hibernate)?
Any hints or suggestions are welcome. I guess it should be possible to do but some initial ideas would be helpful. Thanks!
I wondering why people need all this schemas, design patterns and so on. Sometimes it is better to write something from lower level. Your task is very good case. In my opinion it's better to write this module in pure jdbc/hql without mappings. It is worth to think about database type. It is not easy to implement dynamic entities in relation based database. Maybe NoSQL database will be better choice.
I'm working on a medium-sized project in Java (GWT to be precise), and I'm still in the process of deciding what ORM to use.
I just refuse to write SQL queries unless utterly and completely necessary (not the case :D)
I want to use ONLY annotations, no XML configuring [except database location, username, etc], and I DON'T want to create any tables or define them. I want this to be done by the framework completely.
Call me lazy, but I like Java/GWT programming, not creating tables and coping with that sort of things, and it's a plus in my assignment if I actually use an ORM :D
I've considered so far:
Hibernate with annotations: I've found little documentation to get started from ground using this. I've found little examples and alike. It's as if they didn't actually want you to use 100% annotations.
DataNucleus
JDO: It seems interesting, I'd never heard of DataNucleus up to until this week, but it seems extremely mature, and I actually discovered it because Google uses it in GWT, so that's a good sign. I also like the fact that they mentioned I don't need to define any tables or columns, though I think hibernate can achieve this as well. I actually enjoyed reading though their documentation (though I haven't finished yet), something quite opposite to hibernate.
JPA I'm not totally sure if DataNucleus/JPA can work with annotation-only configuration, though I might need to take a deeper look into the documentation.
As you might guess, I'm quite inclined to JDO... but it'd be nice to hear what people who've used it have to say vs the other alternatives, and if i'm missing some very important point here.
Edit 1: I know I'll need to XML the database location/usr/pwd, I meant I don't want to use an XML to configure the mapping or database schema.
JPA (1 and 2) is pretty much XML free, depending on how it's packaged. You most certainly don't need it for the schema. It also supports annotations for details when the tables are generated.
The only issue with these is that while they can create a database, they're a DB MAPPING tool, not a DB DEFINITION tool. Specifically, most won't allow you to create the arbitrary indexes that you may well need to get the DB tuned properly to your queries.
But other than that, JPA should fill your needs, and it has a lot of implementations (Hibernate is just one implementation).
This is a self publicizing but I'm been working for a while on a simple Java ORM package called ORMLite. I wanted something much less complicated than hibernate but without writing SQL directly. It's completely annotation based and currently supports MySQL, Postgres, Derby, and H2. Adding other database would be simple if I have access to a server. It is completely annotation based and can create (and destroy) tables.
http://ormlite.com/
It has pretty flexible QueryBuilder and table paging. Joining is, however, not supported.
Hi everybody: let me do a bit of "concept mining" here: I am involved in mantaining/extending an application whose functionality is distributed across several servers. For example, we have a machine running the ApplicationServer, another running the DataServer and so on.
This application has a Web Interface. The current UI is totally implemented in Java, and in a way that makes adding new functionality hard. One of my goals is extending this interface, and we're considering shifting the whole thing to another platform, like Rails, for example.
Problem being, the database that is manipulated by the UI (possibly Rails in the future) is also manipulated by ApplicationServer (Java).
So, my main question is: both Rails and Java can access databases through their own ORM (ActiveRecord for Rails and Hibernate or similar for Java). Is there any way to guarantee that the mappings are consistent?*
Even if the answer is a hard "no", I'd also like to hear your thoughts on how you'd approach this scenario.
I hope the question is clear enough, but warn me if it isn't and I'll edit accordingly. =D
*Edit: per request, I'm extending this explanation: what I mean is, how to make sure things don't break when someone needs to add a new field to the database and edits the Hibernate mapping because of it? I know that Rails "guesses" the entity attributes pretty much by itself (making things easier), but I was wondering if there was some "magical way" to "connect" the ActiveRecord directly to the Hibernate mapping.
Depends on your case and how important it is to actually ensure that things won't break. I would probably code the Rails app to do its best, and then write a good set of db integration test cases for Rails to test against breakage.
Because Hibernate needs a mapping conf whereas Rails uses the database layout directly, it's best to do the db changes on Hibernate/mapped Java class side and then run the test suite on Rails side after changes.
this might be coming too late to the party, but ActiveJDBC is an ActiveRecord- like implementation in Java which reads metadata and configures self pretty much the same as ActiveRecord: http://code.google.com/p/activejdbc/
You should look at using DataMapper instead of ActiveRecord. DataMapper and Hibernate following roughly the same pattern so the mappings would be similar. Also, DataMapper defines the mapping in the class itself rather than figuring it out from the model. This is much closer to Hibernate and you could probably write a simple hbm to dm converter and just eval the output at the top of your model classes. If you didn't design your original data model with Rails in mind, none of the convention over configuration standards are likely to be there; with DataMapper, the default seems to be to map properties and relationships like Hibernate.
Another idea: if you use the Hibernate annotations instead of xml mapping, maybe you could JRuby as the bridge to build the Ruby model from the Java one.
But either way, if you have good tests, it should be obvious when a data model change break something.
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.