How to simulate NVL in HQL
The equivalent to the nvl command in HQL is the coalesce command. coalesce(a,b) will return a if a is not null, otherwise b. So you would want something on the lines of: from Table where col1 = coalesce(:par1, ‘asdf’)
The equivalent to the nvl command in HQL is the coalesce command. coalesce(a,b) will return a if a is not null, otherwise b. So you would want something on the lines of: from Table where col1 = coalesce(:par1, ‘asdf’)
I think that the section 15.6. The select clause covers what you’re trying to achieve: 15.6. The select clause … Queries can return multiple objects and/or properties as an array of type Object[]: select mother, offspr, mate.name from DomesticCat as mother inner join mother.mate as mate left outer join mother.kittens as offspr Or as a … Read more
Wow, just fixed the problem. sessionFactory = configuration.buildSessionFactory(new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry()); I was missing the .applySettings(configuration.getProperties()) Learnings configure() should be called AFTER setProperty Use hibernate.connection.url and NOT connection.url if you use hibernate.dialect=org.hibernate.dialect.MySQLInnoDBDialect Set log4j property for hibernate logs to ALL, so that you can see more detailed issues To get rid of the WARN Recognized obsolete hibernate … Read more
Your approach is correct. Performance throughput? IMHO no need to worry – JPA 2.1 will use an equivalent mechanism. But make sure to write a realistic test to be on the safe side. What happens when there are multiple logged in users updating entities concurrently in their own scopes? All (non-dependend-scoped) bean references are proxied … Read more
Putting down here how I implemented this. Basically we need to make a Hibernate Component (read @Embeddable object) out of the set of columns we need to query on and embed it in the main Entity. The group of columns can be combined as below: @Embeddable public class CompositeColumns{ private String col1; private String col2; … Read more
If you’re using Hibernate 4 and trying to create a EntityManagerFactory manually (or SessionFactory) declared as <jta-datasource>, there is a property you must set on your persistence.xml called hibernate.transaction.jta.platform. For using on JBoss 7 <property name=”hibernate.transaction.jta.platform” value=”org.hibernate.service.jta.platform.internal.JBossAppServerJtaPlatform” /> I found about this property at Hibernate Docs
There is a way to bypass the validation and get it to work, thus indicating the column is a “@JoinColumnsOrFormulas” then put the solution: Error: @ManyToOne @JoinColumns(value = { @JoinColumn(name = “country_code”, referencedColumnName = “country_code”), @JoinColumn(name = “zip_code”, referencedColumnName = “code”)}) private Zip zip = null; @ManyToOne @JoinColumns(value = { @JoinColumn(name = “country_code”, referencedColumnName = … Read more
(1) , (3) : Yes. You are right .Both the load() and get() will first check if there is an instance with the same PK is persisted in the session. If yes , just returns that instance from the session. (It may be the proxy or the actual entity class instance) If no , load() … Read more
https://www.hibernate.org/43.html Basically, you have a few options. -You can use the “open session in view” pattern where you use a filter/interceptor/AOP – style logic to open a session when server side logic begins, and close it when it’s through. -You could implement conversations spanning several request-response cycles. A plain old Servlet Filter is the easiest.
Hibernate requires that entity tables have primary keys. End of story. 50k records is simply not that many when you’re talking about a database. My advice: add an autoincrement integer PK column to the table. You’ll be surprised at how fast it is.