1 / 13

Database support for TPTP EMF based data models using Elver/Hibernate

This article provides an overview of Hibernate and the Elver-Hibernate architecture, along with a sample source code. It also discusses the current TPTP database support and the challenges of persistence. The solution involves using Hibernate for object-relational mapping and Elver for EMF support. The article includes code samples for creating a data store, executing SQL and HQL queries, and creating and loading a resource. It also highlights the benefits of Elver, such as multi-database support, automatic schema generation, exception handling, and annotations support.

russellgreen
Download Presentation

Database support for TPTP EMF based data models using Elver/Hibernate

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Database support for TPTP EMF based data models using Elver/Hibernate Guru Nagarajan July 14, 2006

  2. Outline • What is Hibernate? • Overview of the Elver-Hibernate architecture • Source Sample • Current TPTP database support • Questions

  3. What is the Problem statement? • EMF objects can be persisted in relational databases and retrieved. The persistence and retrieval should support • Most used Relational Databases • Support the retrieval of the EMF objects using the EMF Resource approach • Capitalize on the query and caching capabilities of Relational Databases and use them in building the required EMF Objects

  4. Challenges of Persistence • In-Memory data and Persistence must be kept in sync • The Object Model requirements could change and the persistence data store definition must be modified • Portability of the persistence is an item not to be ignored • Object-Relation Mapping to be seamless • Solution: Application should not need to know that its data is being persisted

  5. Your App Object Hibernate Mapping Database What is Hibernate? • Basically, a Object-Relational Mapping tool • Maps Objects -> Relational Databases • Implements those Mappings • Knows about the underlying Database and provides an elegant abstraction • How does Hibernate work? • At runtime, Hibernate reads the mapping and dynamically builds Java classes that manages database-object interaction. • Provides an API to manage, query the objects from the database, and create objects

  6. EMF Model Database What is Elver? • Elver basically adds the EMF support to Hibernate OR • It consists of primarily two components • Mapping Tier • Support for EMF annotations • Runtime Tier • Query, Save, Create objects using EMF Object Hibernate Mapping EMF Datastore

  7. Elver Runtime Arch.

  8. Elver Code Sample • // Create the DataStore. final String dataStoreName = “YourModelDataStore"; final HbDataStore dataStore = HbHelper.INSTANCE.createRegisterDataStore(dataStoreName); • // Configure the EPackages used by this DataStore. dataStore.setEPackages(new EPackage[] { EMFPackagePackage.eINSTANCE }); • // Initialize the DataStore. This sets up the Hibernate mapping and creates the corresponding tables in the database. dataStore.initialize(); • //start a transaction final SessionFactory sessionFactory = dataStore.getSessionFactory(); // Open a new Session and start Transaction. Session session = sessionFactory.openSession(); session.beginTransaction(); • Create and populate Model Model model = ModelFactory.eINSTANCE.createModel(); //Set Model Properties // Make it persistent. session.save(model); Commit Transaction and close Session • session.getTransaction().commit(); session.close();

  9. Sample – Creating SQL & HQL Queries, Resource • SQL Query • query = session.createQuery("SELECT count(allbooks) FROM Model model WHERE <<>>=<<>>"); • Hibernate Query (HQL) • Query query = session.createQuery("FROM Model.member"); • List modelmember = query.list(); • Creating and Loading Resource String uriStr = "hibernate://?" + YourSessionFactory"; final URI uri = URI.createURI(uriStr); ResourceSet resourceSet = new ResourceSetImpl(); final Resource res = resourceSet.createResource(uri); • //Load the resource res.load(Collections.EMPTY_MAP); Iterator it = res.getContents().iterator(); //Iterate through the iyterator to get your model objects

  10. TPTP Database Support - Overview • TPTP database interface is very similar to Hibernate • Database Interface • TypeMap • Paging … • Query Builder • Object Query – Subset of HQL (Hibernate Query) • Reference Query – EMF Query • Support for Log database schema • For other models you have to extend, provide the schema

  11. Why Elver? • Multi-Database support • MySql, Oracle, DB2, Access etc. • Database specific SQL (SQL Diaelect) supported • Exposes the Database performance via SQL queries (Hibernate ftr) • Automatic Schema Generation • Provide a EMF model, set its characteristics and Elver/Hibernate creates the mapping, schema for runtime • Not “Model” Specific • Exception Handling & Logging • Very good exception handling • Log4J Logging • Annotations Support • Preserve the Annotations in the Database • Database Transaction support

  12. Q & A

  13. Useful Links • Elver Page: http://www.elver.org • Hibernate: http://www.hibernate.org • License: • Elver: Apache 2.0 • Hibernate: LGPL

More Related