Here are two ways I know of to update an entity in the database without doing a retrieval of the entity first: //Assuming person is detached from the context //for both examples public class Person { public int Id { get; set; } public string Name { get; set; } public DateTime BornOn { get; … Read more
The issue can be a conflict between a java version and a javaassist version. If you’re using the java 8 on your server you should make sure to use the latest javassist version as well. This blog shows the origin of a conflict being inside the thymeleaf which pulls in an older javassist, the solution … Read more
equals() and hashCode() should be implemented using a business key – i.e. a set of properties that uniquely identify the object, but are not its auto-generated ID. in toString() you can put whatever information is interesting – for example all fields. Use your IDE (Eclipse, NetBeans, IntelliJ) to generate all these for you. In order … Read more
It is theoretically correct but SQL server (not Entity framework) doesn’t like it because your model allows single employee to be a member of both First and Second team. If the Team is deleted this will cause multiple delete paths to the same Employee entity. This cannot be used together with cascade deletes which are … Read more
EF Core 3 To take Ryan’s example: protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<SomeTable>(entity => entity.HasCheckConstraint(“CK_SomeTable_SomeColumn”, “[SomeColumn] >= X”); } Docs. EF Core 7+ protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder .Entity<Blog>() .ToTable(b => b.HasCheckConstraint(“CK_Blog_TooFewBits”, “Id > 1023”)); } See this for more details and changes in 7. Docs.
@Entity annotation defines that a class can be mapped to a table. And that is it, it is just a marker, like for example Serializable interface. And why @Entity annotation is mandatory? … well, it is the way how JPA is designed. When you create a new entity you have to do at least two … Read more
A detached entity is an entity whose state must not be reflected by the JPA provider. In other words, if you change its state (i.e. through setters methods) these changes will not be saved to the underlying database, as the JPA provider doesn’t have to “observe” such entities. If entity E1 is a managed entity … Read more
This is a limitation of EF that I reported in 2012 https://entityframework.codeplex.com/workitem/483 that is still not implemented in 6.0.2. EF uses a flat internal architecture and does not recognize namespaces. Might be coming in EF7 but not before. For now the only solutions is to rename the two classes to unique class names irrespective of … Read more
Symfony2 with Doctrine as default ORM will automatically generate an ID after data stored in database. So you can call the ID by ->getId() $id = $person->getId();
There are several way to solve it: As described in Do I need <class> elements in persistence.xml?, you can set hibernate.archive.autodetection property and Hibernate should be able to look up all annotated classes from classpath. However, that’s not JPA spec compliant. If you are using Spring, from Spring 3.1.2 (or probably even a bit earlier), … Read more