one-to-one

I have two examples that first is @OneToOne unidirectional mapping and second bidirectional. In unidirectional mapping, the owning-side table must contain a join column that refers to the other table's id; then in bidirectional both of them must contain a foreign key column for each other. But after generating the database schema with autogenerate strategy, two examples have the same effect on database schema. Unidirectional mapping is normal but the bidirectional example only contains one foreign key column, but it must be involve each other's foreign key! Unidirectional Mapping @Entity

Let's say I have Person class Person{ @Id Integer id; @OneToOne @JoinColumn(name = "person_id") Job myJob; } and Job class Job{ @Id Integer id; Integer person_id; @OneToOne @PrimaryKeyJoinColumn(name = "person_id") Person currentWorker; } I'm not able to map the Person and Job to other Entity, when fetching. What mistake am I doing ? Guaido79 Your code should be: @Entity public class Person implements Serializable { @Id Integer id; @OneToOne @JoinColumn(name = "id") Job myJob; } @Entity public class Job implements Serializable { @Id Integer id; @OneToOne(mappedBy = "myJob") Person

I have two models in Django that are related with a OneToOneField ( PrinterProfile and PrinterAdress ). I am trying to do a form with PrinterProfileForm , but for some reason it does NOT pass the PrinterAddress fields into the form (it's not rendered by Django "magic" in the template). What should I do so that my PrinterProfileForm include as well the fields from PrinterAddress (its related OneToOneField )? Thanks a lot class PrinterProfile(TimeStampedModel): user = models.OneToOneField(User) phone_number = models.CharField(max_length=120, null=False, blank=False) additional_notes = models

I'm trying to get Hibernate @OneToOne annotations working and not having much success here... Let's say I've got a table called status that looks like this: +------------------------------------------------+ | status | +------------------------------------------------+ | id | frn_user_id | frn_content_id | status | +----+-------------+----------------+------------+ | 1 | 111 | 0 | "active" | +----+-------------+----------------+------------+ | 2 | 0 | 222 | "inactive" | +----+-------------+----------------+------------+ And I've got an entity for User that looks like this: @Entity @Table(name

I am having a hard time trying to figure out when to use a 1-to-1 relationship in db design or if it is ever necessary. If you can select only the columns you need in a query is there ever a point to break up a table into 1-to-1 relationships. I guess updating a large table has more impact on performance than a smaller table and I'm sure it depends on how heavily the table is used for certain operations (read/ writes) So when designing a database schema how do you factor in 1-to-1 relationships? What criteria do you use to determine if you need one, and what are the benefits over not using one

I’m working with an existing schema that I’d rather not change. The schema has a one-to-one relationship between tables Person and VitalStats, where Person has a primary key and VitalStats uses the same field as both its primary key and its foreign key to Person, meaning its value is the value of the corresponding PK of Person. These records are created by external processes, and my JPA code never needs to update VitalStats. For my object model I’d like my Person class to contain a VitalStats member, BUT: When I try @Entity public class Person{ private long id; @Id public long getId(){ return