Use @UniqueConstraint: @Table( uniqueConstraints= @UniqueConstraint(columnNames={“author_id”, “number”}) ) @Entity class Book extends Model { @ManyToOne @JoinColumn(name = “author_id”) User author; int number; }
I fixed the issue by changing the code to @Basic(optional = false) @Column(name = “LastTouched”, insertable = false, updatable = false) @Temporal(TemporalType.TIMESTAMP) private Date lastTouched; So the timestamp column is ignored when generating SQL inserts. Not sure if this is the best way to go about this. Feedback is welcome.
AOF stands for Append Only File. It’s the change-log style persistent format. RDB is for Redis Database File. It’s the snapshot style persistence format.
iBATIS and Hibernate are quite different beasts. The way I tend to look at it is this: Hibernate works better if your view is more object-centric. If however you view is more database-centric then iBATIS is a much stronger choice. If you’re in complete control of your schema and you don’t have an extremely high … Read more
JPA Annotation Meaning for Many to Many relationships: ALL – all possible cascading operations performed on the source entity are cascaded to the target of the association. MERGE – if the source entity is merged, the merge is cascaded to the target of the association. PERSIST – if the source entity is persisted, the persist … Read more
JPA implementations have the choice of managing transactions themselves (RESOURCE_LOCAL), or having them managed by the application server’s JTA implementation. In most cases, RESOURCE_LOCAL is fine. This would use basic JDBC-level transactions. The downside is that the transaction is local to the JPA persistence unit, so if you want a transaction that spans multiple persistence … Read more
I usually use getReference method when i do not need to access database state (I mean getter method). Just to change state (I mean setter method). As you should know, getReference returns a proxy object which uses a powerful feature called automatic dirty checking. Suppose the following public class Person { private String name; private … Read more
Mozilla implements it like cookies: DOM Storage can be cleared via “Tools -> Clear Recent History -> Cookies” when Time range is “Everything” (via nsICookieManager::removeAll) https://developer.mozilla.org/en/DOM/Storage In DOM Storage it is not possible to specify an expiration period for any of your data. All expiration rules are left up to the user. In the case … Read more
@Entity(name = “someThing”) => this name will be used to name the Entity @Table(name = “someThing”) => this name will be used to name a table in DB So, in the first case your table and entity will have the same name, that will allow you to access your table with the same name as … Read more
@Basic signifies that an attribute is to be persisted and a standard mapping is to be used. It has parameters which allow you to specify whether the attribute is to be lazily loaded and whether it’s nullable. @Column allows you to specify the name of the column in the database to which the attribute is … Read more